The Ebul Fetih Cami, 1247 (so older than the Yunus Emre Camisi, 1349, but heavily restored).

On the picture: The building inscription of the mosque, written in sülüs script, and placed above the entrance door to the prayer room. It states the date, and the name of the builder of both the mescit (small mosque) and the adjacent türbe (tomb): Ebu Bekr oğlu Saadettin Ali Bey, a state official serving under the Seljuk sultan Keykavus II.

(From Wikipedia): Sülüs (from Arabic: ثلث‎ ṯuluṯ "one-third"), also referred to as ‘thuluth’, is a script variety of Islamic calligraphy, invented in Persia and making its first appearance in the 11th century AD. The straight angular forms of the older Kufic script were replaced in the new script by curved and oblique lines. In Sülüs, one-third of each letter slopes, from which the name (meaning "a third" in Arabic) comes. It is a large and elegant, cursive script, used in medieval times on mosque decorations.

Correspondent: J.M.Criel, Antwerpen.
Source: ‘Karaman (Tarihi ve Kültürü)’ (Ilhan Temizsoy & M. Vehbi Uysal) – Konya 1981 & Wikipedia.