Osman Shah Mosque, Ottoman congregational mosque in Trikala, Greece.

The Osman Shah Mosque is a former Ottoman mosque in central Trikala, Greece, listed as an archaeological site. Its square prayer hall is covered by a large semi-spherical dome about 18 metres in diameter, and the lead sheeting on that dome gave the building its Turkish nickname, Kurşun, meaning lead. The front portico was completely rebuilt in the 1998 renovations, and the ashlar minaret stands at the northwestern corner, well preserved apart from its missing roof.

The building was erected in the mid-1500s by the Ottoman governor of the region as a gift to the city of Trikala. It is attributed to the architect Mimar Sinan, the leading builder of the Ottoman Empire at that time.

The name Kursum, from the Turkish kurşun (lead), refers to the lead-covered dome. Tradition holds that Osman Shah built the mosque after being cured in Trikala of an illness, and he was buried in the octagonal türbe beside it after his death in 1567/8. The building now serves as a venue for mild events.

The mosque stands in the center of Trikala and can easily be reached on foot from the main streets of the city. It is worth checking in advance whether the interior is open, as it can sometimes be closed for events or upkeep.

Mimar Sinan, to whom this building is attributed, also designed the Selimiye Mosque in Edirne, which he considered his finest work. Finding a building tied to his name in a small Greek city is therefore a rare encounter with that chapter of architectural history.