What did great zimbabwe believed to be

Great Zimbabwe is believed to have served as a royal palace for the local monarch.

Explanation:

It would have been used as the seat of political power. Among the edifice's most prominent features were its walls, some of which were over five meters high.

Great Zimbabwe was the heart of a thriving trading empire from the 11th to the 15th centuries. The word zimbabwe, the country's namesake, is a Shona (Bantu) word meaning "stone houses."

Lusvingo, now called Great Zimbabwe, is the largest stone structure in precolonial Southern Africa ... This kingdom was destroyed by the Nguni, first Zwangendaba and later on Mzilikazi.

have served as a royal palace for the local monarch.