Mohammed calms the dragon. The scene comes not from the Koran but from the "Siyer-I Nebi", an epic about Mohammed. Lufti Abdullah was the calligrapher in charge of this edition, completed in 1595. Topkapi.
This image of Mohammed comes from one of the older surviving Turkish manuscripts. The Turks were semi-literate and their first documents date to the 8th century, long before they as a people arrived in Turkey. It seems they were not yet Muslim at the time, and battling successors and followers of the historical Mohammed in Central Asia.