During 570 A.D. a man was born his name was Muhammad, he was born very near a the ancient shrine named Ka'ba. When he was very young his parents died, and the uncle adopted him.
Many years later Muhammad married a rich 24-year-old widow and became a merchant. When Muhammad was 40 years old he had his first revelation while he was in a cave outside of Mecca, and he heard ringing of bells, then he started to see messages and he was told in these messages he would be the prophet of a new religion and that he had to prophecy to the world
In 622 Muhammad decided to move to Medina for safety because of the first 2 years his new religion was not well received by his city, his family, and friends. When he moved to Medina, the city welcomed Muhammad's new religion and was one of the first city to turn into and Islamic country, and within the first few month's Muhammad became the new ruler over Medina. After becoming the leader of Medina he led many battles against Mecca and soon capturing it and turn it into a Islamic city.
He also led a pilgrimage which he walked Medina to Mecca and visit the Ka'ba shrine, few month's later he fell ill and died.
The first 4 Caliphs after Muhammad were known as the Rashidun Dynasty, all four of these leaders were elected to become the Islamic people leader.
The first caliphs were family members, the first caliph was Abu-Bakr( Father-In-Law), the second Umar, the third Uthman, and finally Ali.
There were also other Dynasty but I do not have enough time to write about each dynasty.