The series follows the rise of the Borgia family to the pinnacle of the Roman Catholic Church and their struggles to maintain their grip on power. The beginning of the first season depicts the election of Rodrigo Borgia to the papacy through simony and bribery with the help of his son, Cesare. The triumph in the papal conclave of Borgia, who becomes Pope Alexander VI, enrages his rivals in the College of Cardinals, some of whom decide to plot against him. With the help of his family, Alexander takes on his enemies while striking alliances with other European powers to strengthen his position.
Meanwhile, Alexander's great rival, Cardinal Della Rovere, travels across Italy and France to seek allies to depose the pope. He manages to persuade King Charles VIII of France to assist him in removing Pope Alexander in exchange for supporting the King's claim to the throne of Naples, an ally of the Borgias through marriage. Season one culminates with Charles and his army, accompanied by Della Rovere, marching to Rome and finally coming to a head with the Borgias.

The cast:
Jeremy Irons as Rodrigo Borgia / Pope Alexander VI
François Arnaud as Cesare Borgia
Holliday Grainger as Lucrezia Borgia
Joanne Whalley as Vanozza Cattaneo
Lotte Verbeek as Giulia Farnese
David Oakes as Juan Borgia
Sean Harris as Michelotto Corella
Aidan Alexander as Joffre Borgia
Colm Feore as Giuliano della Rovere

Trailer: