Moorea (pronˌmoʊ.oʊˈreɪ.ɑː or ˈmoʊ.oʊreɪ; Moʻoreʻa, moʔore(ʔ)a), also spelled Moorea, is a volcanic island in French Polynesia. It is one of the Windward Islands, a group that is part of the Society Islands, northwest of Tahiti. The name comes from the Tahitian word Moorea, meaning "yellow lizard": Moo = lizard ; Rea (from rearea) = yellow. An older name for the island is Aimeho, sometimes spelled Aimeo or Eimeo (among other spellings that were used by early visitors before Tahitian spelling was standardized). Early Western colonists and voyagers also referred to Moorea as York Island or Santo Domingo. According to recent archaeological evidence, the Society Islands were probably settled from Samoa and Tonga around 200 CE. Nine tribal principalities emerged in the enclosed valleys, which in turn were subdivided into individual clans. The stratified society was characterized by a hierarchical leadership whose elite combined both political and religious power. The leading families of Moorea remained linked by marriage and kinship for centuries with those of the neighboring island of Tahiti. These connections led to important alliances, but at other times were also the source of bloody conflicts. Intensive research on the Opunohu Valley, which continues to this day, initiated by Kenneth P. Emory in the 1920s and continued in the 1960s by archaeologist Roger C. Green of the University of Auckland, provides an exemplary picture of the evolution of Moorean society. The interaction between increasing population density and human modification of the environment resulted in major changes in the form of society. The so-called Pre-Atiroo phase, prior to 1000 CE, is characterized by extensive clearing and cultivation of the valley slopes, which by the end of the period had led to erosion and the formation of alluvial soils. Society was not yet stratified, but was relatively homogeneous. In the Atiroo period (1000–1650 CE), artificial cultivation terraces were built on the slopes and simple stone buildings, such as the Marae Tapauruuru.