The son of a prominent Venetian family, Nicholas Giustiniani had at first intended to spend his life
in the Venetian Benedictine monastery of San Niccolo del Lido, but he was compelled by his obligations to his family
to marry after all his brothers were slain in battle at Constantinople, Hilda Graef and a plague further decimated the Giustiniani lineage. Nicholas wedded Anne Michieli, the daughter of a Venetian doge. They had nine children, six sons and three daughters. Around the year 1160, the couple agreed to separate so as to allow Nicholas to fulfill his original aspiration
of devoting himself to God
as a monk
of the San Niccolo monastery. Here he led a very humble and penitent life. After procuring the foundation
of a new monastery at Torcello, Anne also left the world, becoming a nun of the convent
of "Saint Blaise of the Giudecca," near Venice.