The drawing which comes from the same source as lot 109, may well have been intended as a study for the series of heads of bearded men used for the bases of bronze angels in the Cathedral at Siena. The type is similar too, although less idealised than those of the heads in this series, and it seems reasonable to suppose that studies of the kind served as the basis for the more definitive designs for the anthropomorphic heads, of which lot 109 is the only known survivor.