Leonardo was born on 15 April 1452 (Old Style), "at the third hour of the night"[nb 4] in the Tuscan hill town of Vinci, in the lower valley of the Arno River in the territory of the Medici-ruled Republic of Florence.[9] He was the out-of-wedlock son of the wealthy Messer Piero Fruosino di Antonio da Vinci, a Florentine legal notary, and Caterina, a peasant.[8][10][nb 5] Leonardo had no surname in the modern sense, "da Vinci" simply meaning "of Vinci": his full birth name was "Lionardo di ser Piero da Vinci", meaning "Leonardo, (son) of (Mes)ser Piero from Vinci".[9] The inclusion of the title "ser" indicated that Leonardo's father was a gentleman.