Built in 908 CE on the remains of a shrine from the sixth century, the Fenari Isa Mosque first began its worldly service as a nunnery inaugurated by Byzantine admiral Constantine Lips.
Henceforth referred to as the Lips Monastery, it was one of the largest of its kind in Constantinople. After the restoration of the Palaiologian dynasty in 1261, the widow of Emperor Michael Palaiologos built a church just south of the Monastery which - over the next few centuries - was gradually built up and renovated to such an extent that the two structures became one.
As an interesting sidenote: Admiral Constantine Lips had a son named Bardas Lips. I just think that deserves mentioning.