On the picture: Although the mosque and its ‘külliye’ (a complex of buildings, centered around a mosque and managed within a single institution) were finished in 1722, the elegant calligraphic inscription on this ‘çeşme’ is dated 1123 H. (= 1711/1712 AD).

A çeşme (a kind of fountain) is a piece of architecture which pours water into a basin to supply drinking water.
They were connected to springs or aqueducts. Until the late 19th century most ‘çeşme’ operated by gravity, and needed a source of water higher than the fountain, such as a reservoir or aqueduct, to make the water flow.
In addition to providing drinking water, fountains were used for decoration and to celebrate their builders, which were generally high state officials, whose name would be mentioned on the ‘kitâbe’ (= building inscription).

Correspondent: J.M.Criel, Antwerpen.
Sources: Websites of ‘istanbuluseyret.com’ – ‘istanbuldakicamiler.com’
& ‘Guides Bleus: Turquie’ – Edition 1986 .