The 19th century aristocrat, Lady Maria Cartwright, known as Lili, was an ardent collector of glass and ceramics. As the wife of a British diplomat, she travelled widely within Europe, taking every opportunity to visit auctions and dealers. Her remarkable collection of early Venetian and façon de Venise glass leads Bonhams Fine Glass and British Ceramics sale in Knightsbridge on Tuesday 29 September. It includes a very rare Venetian enamelled glass pilgrim flask from around 1500, bearing the arms of the prominent Nerli family of Florence, estimated at £20,000-30,000.

Lady Cartwright started collecting glass and ceramics in Munich in the 1820s before her marriage, when she was Countess von Sandizell. She continued to collect until her death in 1902, aged 97. The exceptional unpublished collection, which was augmented by Lili's eldest son William in the late 19th century, has remained in the Cartwright family ever since; until the middle of the 20th century it was on display at the family seat of Aynhoe Park, in Oxfordshire.

Bonhams specialist in European Glass, Jim Peake, said: "These fragile pieces, which have survived for between 300 and 500 years, represent some of the most significant examples of early Venetian and façon de Venise glass to come to auction for many years. Some pieces are appearing on the market for the first time in nearly two centuries."

Other highlights include:

• A façon de Venise gilded, enamelled and engraved vase and cover made at the Court Glasshouse, Innsbruck, between 1570-9. In 1570 Archduke Ferdinand II of Tyrol, tired of relying on Venice for luxury tableware, founded a glasshouse in the garden of his new home at Schloss Ambras, Innsbruck. He persuaded the Venetian authorities to lend him craftsmen from Murano and obtained permission to use various raw materials and tools brought from Venice. The Archduke also employed around 50 painters each with different artistic talents, who were most likely German. The cold-painted decoration on these wares was usually executed in red, green and gold, reflecting Germanic taste. Estimate: £20,000-30,000.

• A very rare Venetian enamelled and gilded low footed tazza with a recumbent stag, made in the first quarter of the 16th century. The tazza belongs to a distinctive group of vessels all painted with medallions in a very similar style and palette, dating to the first quarter of the 16th century. A small number of these include deer or stags and the treatment of the grass, painted in bright green with tiny lines or shapes painted in black, together with the rendition of the sun with distinctive linear dashed rays, suggests they may have been decorated in the same workshop in Venice, perhaps even by the same craftsman. Estimate: £10,000-15,000.