The Four Caliphs of Islam

The four caliphs of Islam were Abu Bakr, Umar, Uthman, and Ali. Together, the four make up the Rashidun caliphs, as they were the first to succeed at ruling after the Prophet Muhammad. The first caliph, Abu Bakr reigned the shortest amount of time, 2 years from 632-634 CE. I have a question about his death, as the video only states that he died at age 61, and did not specify the cause. The second of the four caliphs was Umar ibn Al-Khattāb, or more commonly known as Umar. He reigned for ten years, starting from 634 and ending at 644 CE. During his reign, the Islamic empire greatly expanded, as he was taking over a lot of land. Umar's ruling unfortunately came to an end in 644, where he was assassinated by a Persian slave. The third Islamic caliph was Uthman ibn Affan, or Uthman. He ruled for the long amount of time, 12 years, from 644-656 CE. He is most commonly known for establishing the version of the Quran which we see to this day. His reign came to an end in 656 CE where he was murdered by rebels in his own house. The final of the four Islamic caliphs was Ali ibn Abi Talib, or Ali. He reigned for five years, from 656 CE to 661 CE. Ali was most known for being the first male to convert to Islam, along with his close connection with Muhammad, as he was his cousin & son-in-law. His life came to an end in 661 CE, where he was assassinated while praying at the Great Mosque of Kufa. Something that surprised me after watching the documentary is that all the the caliphs which we know the cause of their death, were assassinated. It makes me wonder if during that time Islam was a safe place, as their leaders were all killed the same way. After watching the video about the caliphs and also digging deeper with more research about them, I have learned a lot of new things about them which I have never knew before.