Abu Bakr al-Siddiq (RA) — 1st Caliph
632–634 CE · The Rightly-Guided Caliphs
Abu Bakr becomes the first Caliph through shura (consultation). He faces three immediate crises: the death of the Prophet ﷺ, emergence of false prophets, and the Ridda (apostasy) wars as tribes refuse to pay Zakat. He suppresses the Ridda, preserving Islamic unity. Mortally wounded after just two years, he commands Umar (RA) as his successor.