Title: Naẓarīyāt al-khalīfatayn
First published: 1998
Subjects: Caliphate, History
Places: Islamic Empire
People: ʻUmar ibn al-Khaṭṭāb Caliph (d. 644), Abū Bakr Caliph (d. 634)
Time periods: 622-661
LC classification: \DS\38.1\.T326