See Vol. I., Age of the Despots, p. 310, note 2.
Crowe and Cavalcaselle, vol. ii. chap, xvi., may be consulted as to the several claims of the two brothers.
His bas-reliefs on Giotto's campanile of Grammar, Astronomy, Geometry, Plato, Aristotle, &c.c., are anterior to 1445; and even about this date there is uncertainty, some authorities fixing it at 1435.