Ömer bin Ibrahim is the builder of the Old Mosque of Edirne, completed 1414 under Mehmed I. He is also known to have built the Yildirim Baths in Mudurnu district of Bolu (b.1382) and the Orta Baths in Bolu (b.1389), where his signature is carved onto the keystone of entry arch.
Sources: AYVERDI, Ekrem Hakki. Osmanli mi'marisinin ilk devri : Ertugrul, Osman, Orhan Gaaziler, Hüdavendigar ve Yildirim Bayezid 630-805 (1230-1402) : I. Baha Matbaasi: Istanbul, 1966. AYVERDI, Ekrem Hakki. Osmanli mi'marisinde Çelebi ve II. Sultan Murad Devri 806-855 (1403-1451): II. Baha Matbaasi: Istanbul, 1972.