What is "orphanotrophos"

Orphanotrophos was a Byzantine title for the curator of an orphanage (ὀρφανοτροφεῖον, orphanotropheion). The director of the most important orphanage, the imperial orphanage in Constantinople, established in the 4th century and lasting until the 13th century, eventually rose to become an office of particular significance and ranked among the senior ministers of the Byzantine state.