Pietro was the son of Federico Cornaro of the Santa Lucia branch.
[1] Being one of the wealthiest Venetian patricians of his age, Federigo could afford to conduct his own foreign policy.
[1] Historian Anthony Luttrell proposes that Federigo arranged Pietro's marriage with Maria of Enghien, Lady of Argos and Nauplia, in 1377 most probably because he wanted to establish a commercial basis in the Peloponnese.
[1] Heavy taxation during the War of Chioggia and a financial crisis menaced the family's position, but Pietro could keep his lordship after his father died in 1382.
[2] Pietro was one of the lords in Frankish Greece whom King Peter IV of Aragon informed about his appointment of Bernard of Cornella as his vicar-general in the Duchy of Athens on 17 August 1387.