Pantaleone Giustinian
Pantaleone Giustinian (before 1229 – 1286) was a Venetian nobleman and cleric, who served as the Latin Patriarch of Constantinople from 1253 until his death.
Pantaleone Giustinian was the son of Philip Giustinian, lord of the Greek islands of Keos and Serifos after the Fourth Crusade. Born in the early 13th century, he is first mentioned in 1229. His appointment to the vacant Latin see of Constantinople was part of a papal effort to secure firm Venetian support for the decaying Latin Empire. For the same reason, to enhance Giustinian's authority, he was also appointed papal legate to the Latin Empire. However, in 1261, Constantinople fell to the restored Byzantine Empire. From then on until his death, Giustinian resided mostly in Venice.
Sources
Gaffuri, Laura (2001). "GIUSTINIAN, Pantaleone". Dizionario Biografico degli Italiani, Volume 57: Giulini–Gonzaga (in Italian). Rome: Istituto dell'Enciclopedia Italiana. ISBN 978-8-81200032-6.