This Renaissance altar with its porphyry inlays and four kneeling angels by Tullio Lombardo (c.1480-1532) dates from the early 1500s and was originally made for the church of San Sepolcro, on the Riva degli Schiavoni, which was suppressed by the Napoleonic authorities in 1808.

It was probably originally designed to be viewed in the round but is installed in San Martino in Castello against the left hand wall. Each of the angels has different features and the distinctive rich, deep undercutting of the hair which can be seen in other figure sculpture by Tullio Lombardo.

Tullio Lombardo came from a family of sculptors working in Venice and was the son of Pietro Lombardo and brother of Antonio who worked together, most notably at Santa Maria dei Miracoli and the Scuola Grande di San Marco. He is best known for his Venetian tomb sculptures, the most famous of which is the Andrea Vendramin monument in SS Giovanni e Paolo. As both architect and sculptor Tullio played a major role in the development of High Renaissance ideas in Venice, bringing his understanding of classical antiquity and familiarity with Tuscan forms to his work.

This project was proposed by John Pope-Hennessy, scholar of the Italian Renaissance, a director of the Victoria & Albert Museum and the British Museum, and an early Trustee of Venice in Peril. Flooding in 1966 had caused accelerated disintegration as salts were absorbed into the marble. Conservation which took place in 1991-2 included desalination and consolidation treatment of the four angels and comprehensive restoration of the altar. It was led by the Australian Committee for Venice, joined by the Swedish, Philadelphia Committees and Venice in Peril Fund.