Bronze medal of Michelangelo, by Leone Leoni

Michelangelo and the artist Leone Leoni (1509-90) may have met for the first time when Leoni worked at the papal mint from 1537 to 1540. By the time that this medal was made in 1560, Leoni was head of the Milan mint and a renowned sculptor. This was a remarkable turn of events for a man who had been convicted of attacking a papal jeweller in 1540. He was sentenced to an indefinite period as a galley slave but was unexpectedly released after just one year.

A great admirer of Michelangelo, Leoni modelled a wax portrait for the medal during a visit to Rome and completed its back, showing life as a pilgrimage, in Milan. The inscription on the back translates as 'I will teach transgressors your ways, and sinners shall be converted to you', and is from the biblical Psalms. He sent four examples to Michelangelo, who in return sent Leoni a wax model of a sculpture. The age, 88, is wrong.