This is the Muradiye mosque, by the greatest Turkish architect, Sinan. It is one of his last works, from 1582-1585, who built it for Murat III.

The, as usual ornate, main entrance. Looking up to the right.

Close-up of the decoration with calligraphic panels under the muqarnas vaulting. The inscription above the door is the mosque’s ‘kitabe’ (building inscription).

Muqarnas is a stalactite-like decoration initiated in Anatolia by the Seljuk (in the 11th – 12th century). They imported it from Iran. Later on it continued to be used in the late-Seljuk architecture of the Beyliks (14th century) and by the Ottomans up to the 19th century. The longer this tradition went on, the more the design tended to become elaborate, even ‘baroque’ in some way.

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Türkye Tarihi Yerler Kılavuzu’ – M.Orhan Bayrak, Inkılâp Kitabevi, Istanbul, 1994 & Wikipedia.