Emperor John VI Kantakouzenos, having from 1343 to 1345 arranged alliances with the Turks, in 1346 marries his second daughter, Theodora, or Nilüfer Hatun, as she will become known, to Orhan, the sixty-two-year-old Ottoman sultan, despite differences of creed and the disparity of age; she elects to remain a Christian.

Theodora's marriage is intended to cement her father's alliance with the rising Ottoman emirate and to prevent the Ottomans from giving their aid to the Empress-regent Anna of Savoy during the ongoing civil war.

Her parents and sisters escort her to Selymbria, where Orhan's representatives, including grandees of his court and a cavalry regiment, arrive on a fleet of thirty ships.

A ceremony is held at Selymbria, where Orhan's envoys receive her and escort her to the Ottoman lands in Bithynia, across the Marmara Sea, where the actual wedding takes place

The splendor of the wedding between Orhan and Theodora at Selymbria (Silivri) is elaborately described by Byzantine writers.