This is the Hekimoğlu Ali Paşa Mosque. He was the son (oğlu) of a court physician (hekim) and himself was Grand Vezir for 15 years under Sultan Mahmut I. The mosque dates from 1734-35, the architect was Ömer Ağa. It has characteristics of the classical style and of the new baroque style.
On the picture: A ‘sebil’ at the corner of the complex.
A sebil is a kiosk-shaped public fountain, with grilled office-windows where attendants handed fresh water over to the public. Generally a sebil had a cellar, where large blocks of ice were brought in during winter. So, in summer, the drinking water could be cooled before distributing it.
Correspondent: J.M.Criel, Antwerpen.
Sources: (amongst others) ‘Guides Bleus: Turquie’ – Edition 1986 & Wikipedia.