Betsiriry is one of the regions settled by communities of internal refugees in Madagascar, whose intermarriage led to the formation of groups known as the Bemihimpa.[4] Most refugees in Betsiriry were of Merina origin, particularly from Vonizongo, Marovatana, and Vakinankaratra areas disproportionately affected by the policies of Queen Ranavalona I or by the unrest following the assassination of Radama II.[5]
Other groups, including Sakalava, Betsileo, Bara, and African or Malagasy slaves, also sought refuge in Betsiriry to escape conflicts in their original homeland or seeking freedom.[5] Betsiriry remained autonomous from surrounding monarchies.[4][5]
By the late 19th century, the Bemihimpa were known as bandits called Fahavalos
[6] who raided Imerina and Betsileo territories. The Bemihimpa leaders of these bands allied themselves with Toera,[6][4] especially Mahatanty,[6] in resisting French colonial troops. Eventually, the Bemihimpa leaders submitted to the French, and Betsiriry was occupied by French forces, with Mahatanty fleeing the region.[1]