Lorenzo Giustiniani was an Italian Catholic patriarch, the first to bear the title of patriarch of Venice; in 1690 it was proclaimed saint by Pope Alexander VIII. Of noble birth, in 1404 he founded together with two other Venetian aristocrats, Antonio Correr and Gabriele Condulmer (later elected pope with the name of Eugene IV), the congregation of the Canons of San Giorgio in Alga (CRSGA), of which he was also elected prior and then general (1424).
After his election to the throne of Peter, in 1433 Eugene IV appointed him bishop of Castello, the diocese of the island of Rialto: when Pope Nicholas V, in 1451, decreed the transfer of the patriarchal dignity from Grado to the seat of Venice, Lorenzo Giustiniani was designated as the first patriarch of the Venetian city. He held this office until his death in 1456.
He was canonized on October 16, 1690 by Pope Alexander VIII.
His liturgical memory is set for January 8 (his dies natalis) and is with St. Mark the Evangelist and the Santissima Annunziata main patron of Venice.