Pope Alexander VI, born Roderic Llançol i de Borja (Castilian Spanish: Rodrigo Lanzol; 1 January 1431 – 18 August 1503) was the head of the Catholic Church from 11 August 1492 to his death in 1503. He is one of the most controversial of the Renaissance popes, and his Italianized Valencian surname Borgia became a byword for libertinism and nepotism, which are traditionally considered as characterizing his papacy. However, his reputation is mostly drawn from his enemies, the Italian prelates and barons whose power he subverted. Two of Alexander's successors, Sixtus V and Urban VIII, described him as one of the most outstanding popes since St. Peter. His reputation rests more on his considerable skills as a diplomat, politician, and civil administrator rather than as a pastor, although regarding the latter he was no less effective than any of the other renaissance pontiffs.
He adopted his mother's family name of Borja in 1455 following the elevation to the papacy of maternal uncle Alonso de Borja (Italianized to Alfonso Borgia) as Calixtus III.
More information on the Wikipedia page [1].