The kingdom was an "ethnic mosaic". In the late 11th century, ethnic Burmans were still "a privileged but numerically limited population", heavily concentrated in the interior dry zone of Upper Burma. They co-existed with Pyus, who dominated the dry zone, until the latter came to identify themselves as Burmans by the early 13th century. Inscriptions also mention a variety of ethnic groups in and around Upper Burma: Mons, Thets, Kadus, Sgaws, Kanyans, Palaungs, Was and Shans. The peoples who lived in the highland perimeter were collectively classified as "hill peoples" ("taungthus", ) although Shan migrants were changing the ethnic makeup of the hill region. In the south, Mons were dominant in Lower Burma by the 13th century, if not earlier. In the west, an Arakanese ruling class who spoke Burmese emerged.