The Medici Seal is a 2006 young adult novel written by Theresa Breslin.

Set among the cultural life and political intrigues of Renaissance Italy, it is the story of a boy who initially calls himself Matteo and his master Leonardo da Vinci.

Ten-year-old Matteo is saved from drowning by friends of Leonardo da Vinci.

Matteo accompanies him both as he pursues knowledge and paints magnificent pictures and as he travels across Italy.

Serving Leonardo da Vinci, seeing first hand the ruthless rule of Cesare Borgia, the ambition of the Medici and the revenge of the dell'Orte.