"He stared dully at the baroque conglomeration of styles that was Topkapi"
topkapipalace
GNU Free Documentation Licensetopkapipalace - Credit: Bjørn Christian Tørrissen

The Topkapi Palace was the official residence of the Ottoman sultan in Istanbul until 1856.

The name means "Cannon Gate".  Construction began in 1459, just six years after the conquest of Constantinople by the Ottomans.