Madagascar contained approximately eighteen ethnic groups during the period described. The Merina, concentrated on the central plateau in Imerina, became the largest and most politically important of these groups during the nineteenth century. Their privileged class established the monarchy that eventually ruled much of the island.

Despite regional differences, the Malagasy groups were presented as one people with profound cultural and ethnic unity. They spoke the same language, with a common grammar and syntax and, for the great majority, the same vocabulary. Their customs and religious traditions were also broadly similar, although exceptions existed.

This shared cultural framework coexisted with political diversity. Merina expansion brought many populations under a common monarchy, but resistance and separate political identities continued in areas such as the Sakalava kingdoms and other regions. Malagasy unity therefore involved cultural commonality without eliminating regional distinctions or political conflict.