Namesakes

Islamic Caliphs: 3 caliphs
Caliph Uthman ibn Affan   644-656   Rashidun  
Caliph Osman II (a.k.a. Uthman)   1618-1622   Ottoman  
Caliph Osman III (a.k.a. Uthman)   1754-1757   Ottoman  
Ottoman Sultans: 2 sultans, 1 bey
Bey Osman I (a.k.a. Uthman)   1281-1326  
Sultan Osman II (a.k.a. Uthman)   1618-1622  
Sultan Osman III (a.k.a. Uthman)   1754-1757