Muslims were not believing that prophet Muhammad (peace be upon him) died and got disturbed and confused until the companion Abou Bakr recited the Quran verse:
""Muhammad is not but a messenger. [Other] messengers have passed on before him. So if he was to die or be killed, would you turn back on your heels [to unbelief]? And he who turns back on his heels will never harm Allah at all; but Allah will reward the grateful." (3:144)
Then they got calmed down. Omar Ibn Alhkattab raised the hand of Abou Bakr and announced that he nominate him as the first Caliph and ruler after prophet Muhammad death. Abou Bakr gained the support of the wide majority and became the first Caliph after the prophet.
Muhammad successfully united Arabian tribes into one Arab Muslim group before he died. Problems created after his death related to disagreement over who would take his place as the leader of the Muslims.
Abou Bakr Assidiq was elected by Muslims as prophet Muhammad (PBUH) successor of the prophet death.
The oldest branch is Al-Sunnah & it was the only one in the time of the prophet Muhammad PBUh.
Preaching hatred and death of non muslims.
They have been in disagreement since the death of the Prophet Muhammad (peace be upon him).
H. Abu Bakar sidique Ra the first caliph was leader of Muslims after death of Prophet Muhammad SAW.
every One Stated To Kill Each Other ! Muslims Were Not Gaining Power .. Wars Broke Out Because After The Death Of Muhammad All The Muslims Got Into A Deep Grief Because Of Which They Loose Many Wars ! The main problem was the succession. There was a disagreement by those who thought it should run in the Prophet's immediate family and those who did not. In the end the latter won with a stopgap candidate, the aged Abu Bakr There was also an apostate rebellion led by one Moseilama (real name prob.Musa). It was crushed.
Umar (omar)
The death of Muhammad split the Muslims over their belief about who should take over as their leader. The Sunnis believed that the person should be elected and the Shiites believed that the person should be a descendant of Muhammad.
Abu Bakr was the leader of the Muslims after the death of the Prophet (peace be upon him)
it was divided by disagreements over which muslims should be leaders
The Sunnis and Shiites were factions of Muslims that divided into separate sects. They are both considered to be Muslims. Neither of them "took over the Muslims." If you are asking which group gained political power first, the answer would be the Sunnis.