Bahrain
After the Battle of Yamamah, Abu Bakr sent Ula bin Al Hadhrami's corps against the rebels of Bahrain. Ula arrived in Bahrain to find the apostate forces gathered at Hajr and entrenched in a strong position. Ula mounted a surprise attack one night and captured the city. The rebels retreated to the coastal regions, where they made one more stand but were decisively defeated. Most of them surrendered and reverted to Islam. This operation was completed at about the end of January 633.
Read more about this topic: Ridda Wars