The city's neighborhoods emerge from historic ethnic, religious and caste divisions. The assignment of certain neighborhoods to particular noble sub-castes under the Kingdom of Imerina established divisions; the highest ranking nobles were typically assigned to neighborhoods closest to the royal palace and were required to live in higher elevation portions of the city. During and after French colonization, expansion of the city continued to reflect these divisions. Today, the ''haute ville'' is mainly residential and viewed as a prestigious area in which to live; many of the city's wealthiest and most influential Malagasy families live there. The part of ''la haute'' closest to the Rova contains much of the city's pre-colonial heritage and is considered its historic part. It includes the royal palace, Andafiavaratra Palacethe former residence of Prime Minister Rainilaiarivony, Andohalothe principal town square until 1897, a cathedral near Andohalo built to commemorate early Malagasy Christian martyrs, the city's most intact historic entrance gate and the 19th-century houses of Merina nobles.