Papers of Friedrich Engels as Corresponding Secretary of the First International for Italy and Spain in 1871-73, comprising his autograph drafts of two outgoing letters and some sixty incoming letters, addressed to Engels as representative of the Central Congress of the First International, and docketed by him, including series of letters by Paul Lafargue, Carlo Cafiero, José Mesa and Francisco Mora, and further letters by Carmelo Palladino, Charles Larroque, Theodor Cuno, Raymond Wilmart, Etienne Lafargue, and others; plus verses "on the fools of the International" in the hand of Laura Marx Lafargue, proclamations, circulars and similar material sent to Engels and the Central Congress; in French, Italian, Spanish, German and English; the papers throughout bearing Engels's characteristic autograph dockets in a mixture of abbreviated German and English, Spanish, French or Italian; comprising in chronological order (as far as sections allow):

A. Italian Congress of the First International

(1) Italian Congress: report (enclosed in letter to Friedrich Engels); headed "Resoconto del Congresso Operaio" addressed to "Cittadini", in scribal hand but signed by Cafiero and docketed by Engels: "Report of – 8 – Delegates/ to Rome Congress, Novbr 71", 8pp, Rome, November 1871; (2) Italian Congress: report (enclosed in letter to Friedrich Engels); headed "Relazione sulla Sezione Napoletana dell'Associazione Internazionale dei Lavorotori", signed and in the hand of Carmelo Palladino and docketed by Engels: "1871. Official Report of Naples Branch", 16pp, Naples, 13 November 1871; (3) Carlo Cafiero: autograph letter signed to Friedrich Engels, 8pp, Barletta, 12 June 1871; (4) Carlo Cafiero: autograph letter signed to Friedrich Engels, 4pp, Naples, 12 July 1871; (5) Carlo Cafiero: autograph letter signed to Friedrich Engels, 4pp, Naples, 10 September 1871; (6) Carlo Cafiero: autograph letter signed to Friedrich Engels, 4pp, Naples, 18 October 1871; (7) Carlo Cafiero: autograph letter signed to Friedrich Engels, 4pp, Naples, 17 November 1871; incorporating an autograph letter by Carmelo Palladino, 3 November 1871; (8) Carlo Cafiero: autograph letter signed to Friedrich Engels, 4pp, Naples, 27 November 1871; (9) Carlo Cafiero: autograph letter signed to Friedrich Engels, 10pp, Naples, 29 November-19 December 1871; (10) Carlo Cafiero: autograph letter signed to Friedrich Engels, 20pp, Milan, 12 June 1872; (11) Friedrich Engels: autograph retained draft of his letter to Carmelo Palladino (in response to 6 above), 2pp, London, 23 November 1871; (12) Friedrich Engels: autograph retained of his letter to Carlo Cafiero (in response to 12 above), 2pp, London, 14 June 1872

B. Spanish Congress of the First International

(13) Francisco Mora: letter signed on behalf of the Spanish Council, to Friedrich Engels, also signed by Gonzalo Mora and the anarchist Anselmo Lorenzo, on headed paper of 'Asociacion internacional de trabajadores', 3pp, Lisbon, 5 July 1871; (14) Francisco Mora: autograph letter signed to Friedrich Engels, 2pp, no date or place; (15) Francisco Mora: autograph letter signed to Friedrich Engels; on headed paper of 'Asociacion internacional de trabajadores', 5pp, Lisbon, 5 July 1871; (16) Francisco Mora: autograph letter signed to Friedrich Engels, 3pp, Lisbon, 12 August 1871; (17) Francisco Mora: autograph letter signed to Friedrich Engels, 1p, Lisbon, 17 August 1871; (18) Francisco Mora: autograph letter signed to Friedrich Engels, stamped in red 'Asociacion Internacional Trabajadores', 1p, Madrid, 24 August 1871; (19) Francisco Mora: autograph letter signed to Friedrich Engels, 1p, Madrid, 24 August 1871; (20) Francisco Mora: autograph letter signed to Friedrich Engels, 3pp, Madrid, 28 August 1871; (21) Francisco Mora: autograph letter signed to Friedrich Engels, 1p, Valencia, 13 September 1871; (22) Francisco Mora: autograph letter signed to Friedrich Engels, 2pp, Madrid, 29 November 1871; (23) Francisco Mora: scribal report signed, submitted to Friedrich Engels; headed: "Compagnons du Conseil federal de la Région" marked "para Alemania", stamped in red 'Asociacion Internacional Trabajadores', 2pp, Madrid, 13 March 1872; (24) Francisco Mora: lithographed circular, docketed by Friedrich Engels, stamp in red of the 'Asociacion Internacional de los Trabajadores 1872 Congreso de Zaragoza', 13 March 1872; (25) Francisco Mora: autograph letter signed to Friedrich Engels; the covering letter to 22 below, 1p, Madrid, 19 March 1872; (26) Francisco Mora: autograph address signed to "Companeros del Consejo general", submitted to Friedrich Engels; stamped in red 'Asociacion Internacional Trabajadores', 3pp, Madrid, 19 March 1872; (27) Francisco Mora and Paul Lafargue: autograph letter signed to Friedrich Engels; the report by Mora on behalf of the Spanish Regional Congress to the General Congress, to Engels, with conjoint covering letter by Lafargue; stamp in red of the 'Asociacion Internacional de los Trabajadores 1872 Congreso de Zaragoza', 2pp, Zaraboza, 8 April 1872; (28) Paul Lafargue: autograph letter signed to Friedrich Engels, 4pp, Madrid, 7 January 1872 (Lafargue often signs himself "Toole Ier" and sometimes addressing Engels, an authority on military matters, as "General"); (29) Paul Lafargue: autograph letter signed to Friedrich Engels (continued in next letter), 4pp, Madrid, 25 January 1872; 30) Paul Lafargue: autograph letter to Friedrich Engels (continuation of previous letter and unsigned), 2pp, Madrid, 26 January 1872; (32) Paul Lafargue: autograph letter signed to Friedrich Engels, 2pp, Madrid, 11 February 1872; (33) Paul Lafargue: autograph letter signed to Friedrich Engels (enclosing item 34), 2pp, 11 February 1872; (34) verses in the hand of Laura Marx Lafargue, comprising sixty lines beginning: "Son los internacionales/ renos monstruos infernales", 3pp; (35) Paul Lafargue: autograph letter signed to Friedrich Engels, 2pp, Madrid, 6 March 1872; (36) Paul Lafargue: autograph letter signed to Friedrich Engels, with covering docket sheet, 4pp, Madrid, 12 April 1872; (37) Paul Lafargue: autograph letter signed to Friedrich Engels (incorporating a letter by Lafargue's son Etienne, aka 'Schnapps'), 6pp, Madrid, 27 April 1872; (38) Paul Lafargue: autograph letter signed to Friedrich Engels, 4pp, Madrid, 2 May 1872; (39) Paul Lafargue: autograph letter signed to Friedrich Engels, 2pp, Madrid, 17 May 1872; (40) Paul Lafargue: autograph letter signed to Friedrich Engels (continuation on smaller separate sheet), 5pp, Madrid, 29 May 1872; (41) Paul Lafargue: autograph letter signed to Friedrich Engels, 2pp, Madrid, 1 June 1872; (42) Paul Lafargue: autograph letter signed to Friedrich Engels, 4pp, Madrid, 5 June 1872; (43) Paul Lafargue: autograph letter signed to Friedrich Engels, 4pp, Madrid, 18 June 1872; (44) Paul Lafargue: autograph letter signed to Friedrich Engels, 2pp, Madrid, 1 July 1872; (45) Paul Lafargue: autograph letter signed to Friedrich Engels, 3pp, Madrid, 12 July 1872; (46) Paul Lafargue: autograph letter signed to Friedrich Engels, 2pp, Madrid, July 1872; (47) Paul Lafargue: autograph letter signed to Friedrich Engels, 4pp, Lisbon, 8 August 1872; (48) José Mesa: autograph letter signed to the Council General of the International, through Friedrich Engels, stamped in red 'Asociacion Internacional Trabajadores', 2pp, Madrid, 11 March 1872; (49) José Mesa: autograph letter signed to Friedrich Engels, 4pp, Madrid, 4 July 1872; (50) José Mesa: lithographed circular to the Spanish Congress (paper-loss at head), stamped in red 'Asociacion Internacional Trabajadores', 1 page, Madrid, 13 March 1872; (51) José Mesa: autograph letter signed to Friedrich Engels, 2pp, Madrid, 25 August 1872; (52) José Mesa: autograph letter signed to Friedrich Engels, 1p, Madrid, 26 August 1872; (53) José Mesa: autograph letter signed to Friedrich Engels, 2pp, Madrid, 2 September 1872; (54) José Mesa: autograph letter signed to Friedrich Engels, 4pp, Madrid, 19 September 1872; (55) José Mesa: autograph letter signed to Friedrich Engels, with original enclosure (newspaper report headed 'Asociaion Internacional De Los Trabajadores', superscribed to the General Congress by Mesa and with the Spanish section's stamp), 4pp, Madrid, 5 October 1872; (56) José Mesa: autograph letter signed to Friedrich Engels (the first two pages incorporating a letter by Raymond Wilmart, the following year representing the First International in Argentina), 4pp, Madrid, 11 October 1872; (57) José Mesa: autograph letter signed to Friedrich Engels, 2pp, Madrid, 25 October 1872; (58) José Mesa: autograph letter signed to Friedrich Engels, 4pp, Madrid, 5 November 1872; (59) José Mesa: autograph letter signed to Friedrich Engels, 3pp, Madrid, 15 November 1872; (60) José Mesa: autograph letter signed to Friedrich Engels, 3pp, Madrid, 1 December 1872; (61) José Mesa: autograph letter signed to Friedrich Engels, 4pp, Madrid, 24 December 1872; (62) José Mesa: autograph letter signed to Friedrich Engels, 3pp, Madrid, 18 January 187[3]; (63) José Mesa: autograph letter signed to Friedrich Engels, 1p, Madrid, 26 January 1873; (64) José Mesa: autograph letter signed to Friedrich Engels, 2pp, Madrid, 3 February 1873; (65) José Mesa: autograph letter signed to Friedrich Engels, 4pp, Madrid, 19 February 1873; (66) José Mesa: autograph letter signed to Friedrich Engels, 4pp, Madrid, 11 March 1873; (67) José Mesa: autograph letter signed to Friedrich Engels, 2pp, Madrid, 27 August 1873; (68) Resolution, signed by the President and four Secretaries, of the Zaragoza Conference of the Spanish Regional Federation of the First International to the General Council in London in support of the Paris Commune, stamp in red of the 'Asociacion Internacional de los Trabajadores 1872 Congreso de Zaragoza', Zaragoza, 1p, 10 April 1872; (69) Printed fragment, headed 'Alto', stamp in red of the 'Asociacion Internacional de los Trabajadores 1872 Congreso de Zaragoza', 1p; (70) Charles Larroque (under pseudonym 'E. Latraque') of the French Congress, in Spanish exile, to Friedrich Engels, 29 July 1873, Santander, 3pp (docketed by Engels as having an enclosure for Buenos Aires); (71) Theodor Cuno (as Federico Capestro): autograph memorandum, headed "La Section 29 des Etats-Unis à la nouvelle fédération madrilaine", 2pp, Madrid, 10 January 1873, some 240 pages, some on lightweight paper, some dust-staining, light foxing, fraying at the edges, occasional very small paper-loss, etc., but overall in good, sound condition throughout, mostly small 4to and 8vo, London, Naples, Madrid, Lisbon and elsewhere, June 1871 to August 1873

'COUNCIL WILL REMAIN EVER LOYAL TO THE FLAG ENTRUSTED TO ITS CARE SEVEN YEARS AGO BY THE FAITH OF THE WORKING MEN OF THE CIVILISED WORLD' – CORRESPONDENCE OF FRIEDRICH ENGELS WITH THE SPANISH AND ITALIAN CONGRESSES OF THE FIRST INTERNATIONAL: a major historical archive charting the struggle for power between the Marxist Central Council of the First International, run by Marx and Engels from London, and the Bakuninite factions that had gained a stranglehold in Spain and Italy; a struggle which, coming as it did soon after the fall of the Paris Commune, was to bring the First International to an end. (This being the so-called 'Red' and 'Black' divide of which Bismark famously remarked: 'Crowned heads, wealth and privilege may well tremble should ever again the Black and Red unite!')

The first International Workingmen's Association – generally known as the First International – had been founded in London in 1864, with Marx attending the inaugural meeting as representative of German labour: 'Although Marx at this time had few supporters anywhere, sheer intellectual superiority immediately made him the leading figure in this organization... Composed of representatives of virtually all tendencies on the European left, ranging from moderate trade unionists to anarchist insurrectionaries, the "International" was to acquire considerable public prominence, coinciding as it did with a marked growth in labour activity and organization in Europe, which it attempted to inspire and co-ordinate... Marx became the chief draftsman of its documents, beginning with its rules and inaugural address (1864), and indeed was chiefly instrumental in holding its disparate elements together until they broke apart under the strain of the battle between Marx, the champion of state power and politics, and Bakunin, the anti-political anarchist, and in the aftermath of the Paris commune of 1871' (E. J. E. Hobsbawm, ODNB).

The battle between Bakunin and Marx was fought out, more than anywhere else, in Italy and Spain. By the time it came to a head, the day-to-day business of the London Central Council had been taken over by Friedrich Engels from the ailing Marx; Engels having sold up his share in the family business in 1868 and moved to London, where he lived near Marx and was able to call upon him every day. (Marx nevertheless is a frequent presence in these letters, especially of course those from his son-in-law Paul Lafargue, and is often referred to as 'Mohr' – or 'Morh' as Lafargue spells it – i.e. the Moor, the name that had been favoured since his student days by his closest associates. While José Mesa signs off many of his letters by asking to be remembered to Marx, Lafargue and his wife, Laura Marx.)

There are, naturally, references to Das Kapital as well as to the Communist Manifesto. Carlo Cafiero, for example, complains that "Yesterday I received a letter on Das Kapital and it seems that K.M. has said or written nothing to Lachatre" (the work's French translator). Or Lafargue writes from Spain: "Here Proudhon is making considerable inroads, his is the most socialist book ever known here. The antidote to his poison is in my hands and I am going to administer it to the Spaniards. I can get Mesa to translate La Misère de la philosophie and publish it, it will certainly be a success and will prepare the way for Das Kapital. But Mesa thinks (and I agree) that you or Marx should write a preface describing the circumstances which gave rise to the refutation, it would be of great historical value... Please show this passage to Marx and ask him to reply to me... What has Marx decided about Das Kapital? Has he seen the contract, has he signed it?" Another letter by Lafargue is written in English and maintains a fiction, for fear of the letter being intercepted, that theirs is a commercial enterprise; it ends "In the next number there will be inserted a furious attack on Mazzini, that will please you and Morh, and is penned by your servitor. I hope you were clever enough to distinguish my writings, which are conceived in Morh's ideas: they will have enough influence here to transform the idealistic theories of our friends, who are more practical than they appear at first sight. Laura has copied for you a piece of verse on the fools of the International. Why do you not send us English newspapers? Send them to Mesa's house – Schnappy [his son] is a little better. My compliments to Mrs Burns [Engels's common-law wife] – Yours faithfully/ Toole".

Engels Letters

The archive contains two important letters by Engels himself, being his retained drafts of letters to the Central Council representatives to the Italian Congress of the First International. The first letter is well known and has often been quoted (and sometimes even misattributed to Marx). It is exceptionally long, written in a minute script on both sides of a strip of paper 400mm. long, and is addressed to Carmelo Palladino, who like his colleague Carlo Cafiero had abandoned Marxism and embraced Bakuninism. It is dated from London on 23 November 1871. The second is to Carlo Cafiero and is dated from London on 14 June 1872. (In quoting from these letters, which are written in French and Italian respectively, we use Rodney Livingstone's English translation from Karl Marx Frederick Engels: Collected Works, volume 44; elsewhere we have made our own translations.)

The letter to Palladino takes the form of an essay-length discussion of the history of the First International, of the opposition it has faced from hostile governments, the internal structure of the International itself, and an analysis of the organization that has been required to maintain it as an effective force. Engels was prompted to write it on being told that the Bakunin faction had triumphed in Naples ("...Since it is evident from your letter that an organised section of the International no longer exists in Naples, I can only assume that the above declaration expresses your individual opinion and not that of the Naples Section, now forcibly dissolved. Being anxious, however, to avoid misunderstandings, I am answering your objections in detail..."). In reply to Palladino's complaint at "the way in which the said Conference was convened, which certainly did not conform to the regulations laid down by our General Rules"; Engels replies, firstly, that "It is indeed true that our General Rules make no provision for Conferences, but only for Congresses; they were drafted in the somewhat naïve belief that governments would leave us to our own devices. Since the governments made it impossible for us to convene a Congress in 1870, the sections, having been directly consulted, confirmed and extended the powers of the General Council, and empowered it to decide upon the time and place at which the next Congress should meet. In 1871 the governments made the meeting of a Congress even more impracticable"; and that "We have proof of this, should you doubt it. But you will not". He points out that, as the Naples Section of the International was no longer being able to meet after 20 August 1871, it could not elect a delegate to the Congress, adding: "And the same goes for France, Germany and Austria; the Federal Council in Spain was forced to take refuge in Portugal! So what could we do? There remained the precedent of 1865 when, for various reasons, the semi-public Congress was replaced by a private Conference held in London, the convening and actions of which were ratified by the next Congress. You might tell me that such precedents are authoritarian and bourgeois survivals unworthy of the true revolutionaries of the proletariat, to which I should reply that the General Rules, Administrative Regulations, resolutions passed by the Congresses, etc., etc., belong in the same category, but that unfortunately no association, however revolutionary, can do without such things. So, the General Council, on its own responsibility, suggested to the sections that the impracticable Congress be temporarily replaced by a practicable Conference, practicable because the delegates would not be known to governments. The sections gave their assent, none protested, and the Council is prepared to answer to the future Congress for its action"; secondly, that "As for the actual convening of the Conference, it was completely in order. All the Federations, all the individual sections in regular communication with the General Council, were notified in good time. But you are a lawyer, as far as I know, and so you should know that in every society written laws coexist with rules laid down by practice. In France, the Association was disbanded; in Spain, Italy, Germany, Austria and Hungary it was harassed by persecutions which totally disorganised it. The only countries where the Internationals could at least gather openly were America, England, Belgium and Switzerland. And even in Belgium a law against the International was promulgated. The election of delegates to a Congress which, in keeping with the Rules, would be expected to hold public sessions alongside administrative sittings became impossible". Furthermore, he reminds Palladino that "if any observations on the legality or the method of convening the Conference were to be made, this should have been done before or during the Conference. None were made".

Engels then responds to Palladino's complaint that there was only a small number of delegates: "For that, the General Council is not to blame. Nonetheless, Belgium, Spain, Holland, England, Germany, Switzerland and Russia were directly represented. As to France, it was represented by practically all the members of the Paris Commune then in London, and I hardly suppose you would dispute the validity of their mandate. If Italy did not send delegates, you must look to your government". He then deals with Palladino's complaint that these delegates have arrogated to themselves the rights peculiar to a General Congress: "This runs completely counter to the facts. The resolutions of the Conference in no way affect the tenor of the Rules. Some merely reaffirm the resolutions of previous Congresses, hardly if at all familiar to sections and members of recent date. Others are of a purely administrative nature. Far from lying outside the competence of a Conference, neither the former nor the latter go beyond even that of the General Council". Palladino has also complained at the very tenor of such resolutions which appear to him to be in "direct opposition to the principles of our Association as laid down in our General Rules"; to which Engels replies: "With this I totally disagree and look to you to provide the proof. The founders of the International, those who drafted the Rules and the resolutions of our Association's Congresses, were very well represented at the Conference, and you will forgive me if, in the first instance, I lend credence to their interpretation of those Rules and to the interpretation given by successive Congresses ever since. Pray do not forget that the International has its own history and that history – of which it has every reason to be proud -- is the best commentary on the Rules; that the International in no way intends to renege that glorious history and that, at this moment, the spontaneous movement of the proletarian masses in favour of our Association -- a movement that is more marked and more enthusiastic in Italy than anywhere else -- is the most striking ratification, not only of the letter of the Rules, but also of the whole of that history. Whatever your fears in regard to the great responsibility the General Council has taken upon itself, that Council will remain ever loyal to the flag entrusted to its care seven years ago by the faith of the working men of the civilised world. It will respect individual opinions, it is prepared to transfer its powers to the hands of its mandators, but as long as it is charged with the supreme direction of the Association, it will see to it that nothing is done to vitiate the character of the movement which has made the International what it now is, and will abide by the resolutions of the Conference until such time as a Congress has decided otherwise".

The letter to Engels's erstwhile friend Carlo Cafiero is prompted by rumours that have reached him that certain of his letters to associates in Italy have been leaked to the press for which he holds Cafiero responsible. Engel takes the opportunity to launch a blistering attack on the Anarchists, in which he compares Bakunin to the Pope and his followers to Jesuits: "I have not written to anyone in Italy other than you... You owe me an explanation of that matter and I expect you to give it to me. I am amazed that you did not supply it as soon as this was published. My letters have nothing to fear from publication, but it is a question of honour for you to inform me whether they were sent to my enemies with your consent or not. If it was done with your consent, I can only come to one conclusion: that you have allowed yourself to be persuaded to join the Bakuninist secret society, the Alliance which, preaching to the profane – behind the mask of autonomy, anarchy and anti-authoritarianism – the breaking up of the International's organisation, practises towards its initiates an absolute authoritarianism, with the aim of taking over the leadership of the Association. It is a society which treats the working masses as a flock of sheep, led by a few initiates whom they follow blindly, and which imitates, within the International, the role of the Jesuits in the Catholic Church. If my conjecture is correct, I must congratulate you on having permanently safeguarded your precious 'autonomy' by delivering it entirely into the hands of Pope Bakunin. But I cannot believe that you, an anarchist and anti-authoritarian of the first water, should have so far forsworn your dearest principles, still less that you could stoop to such depths towards myself, when I have always treated you with the greatest sincerity and trust. In short, you must clarify this matter, and without delay". The draft ends: "Greetings and emancipation. Yours, F. E."

Provenance: When Marx died, his papers were inherited by Engels and their amalgamated papers passed after the latter's death to the German Social Democratic Party. Soon after Hitler came to power, in 1933, the bulk of the archive was smuggled out of Germany; most of the material that survives being acquired by the International Institute for Social History, Amsterdam, in 1938, with about twenty per cent ending up in the Marxist-Leninist Institute of Moscow (now the Russian State Archives).

It appears that the present group of papers originally belonged to the Marx-Engels archive, but was removed before the archive was sold to the IISH, although after photographic copies had been made and deposited at the Marxist-Leninist Institute. (We are most grateful to Dr Henk Wals, General Director of the IISH, for his help in clarifying this point.)

At some point the present group of papers came into the hands of the family of Gustav Mayer, author of the first substantial and scholarly biography of Engels, which was published in two volumes in 1920 and 1936, the latter after he had fled Germany. His son (Jacob) Peter Mayer (who published as J.P. Mayer) also wrote works on Engels but was to become best known as the editor of de Tocqueville's works. Peter Mayer was, in the words of his Independent obituary, 'a leading figure in the anti-Nazi movement in Germany in the mid-1930s'. He was arrested by the Nazis for distributing SDP leaflets, and his flat sealed off by the Gestapo. However during the temporary thaw brought about by the Olympic Games in the first two weeks of August 1936, he secured permission to leave the country on holiday. The family retain in their possession a copy of a letter of 1976 by Peter to the US diplomat Jacob Bean stating that 'My wife and I have often recalled the evening in Berlin when you took us to dinner the day the Gestapo had sealed our rooms'. Family tradition holds that a friendly Swiss diplomat was allowed back into the flat and recovered a small quantity of Engels material, with which Mayer fled to England. He was to be followed by his wife and son a year later.

The Italian section of the First International material, which includes the two Engels letters, is contained in a reused envelope bearing a German Empire postage stamp datable to about 1914. In the top left-hand corner is the return address of Frau Sigmar Mehring: presumably the opera singer Hedwig Lowenstein, who died in 1942, wife of the author Sigmar Mehring, who died in 1915, and mother of the SDP activist and satirist Walter Mehring. Over it is pasted a label listing the contents, including the two Engels letters, in what we believe to be Gustav Mayer's handwriting. The Spanish material was originally held in three bundles, each secured by a near-identical band of paper cut from what appears to a magazine cover or poster, showing a worker stripped to the waist smashing a swastika with a hammer: as each strip duplicates each other, whoever was responsible had access to either multiple proofs or copies of the publication in question. This suggests that they may have been bundled up by Peter Mayer. Each letter bears an inventory number in pencil, with rectos and versos being indicated by letters of the alphabet: this was no doubt done when photographic copies were made for the Moscow archives.

Accompanying the archive is a group of typescripts, galley proofs, correspondence, notes and pamphlets by Mayer father and son, principally relating to Marx and Engels.

The Engels drafts have been published from the photographic copies in Moscow (see above). Similarly, Giuseppe De Bo prints the Italian section from these copies (or another set at the Istituto Giangiacomo Feltrinelli) in Marx e Engels: Corrispondenza con italiani 1848-1895 (1964). Émile Bottigelli was not able to trace our letters when he published Correspondance: Friedrich Engels et Paul & Laura Lafargue (1956), but notes: 'Celles qui furent adressées à Engels par Lafargue alors que celui-ci état en Espagne, en 1871-1872, se trouvaient dans les archives du parti social-démocrate allemande, où Gustav Mayer put encore les consulter avant 1933' (vol. I, pp. vii-viii).