In Polynesia, the complex Society Islands chiefdoms constructed elaborate temples (
marae
), some of which reached monumental proportions and were associated with human sacrifice in the ‘Oro cult. We investigated the development of temples on Mo‘orea Island by
230
Th/U dating of corals used as architectural elements (facing veneers, cut-and-dressed blocks, and offerings). The three largest coastal
marae
(associated with the highest-ranked chiefly lineages) and 19
marae
in the inland ‘Opunohu Valley containing coral architectural elements were dated. Fifteen corals from the coastal temples meet geochemical criteria for accurate
230
Th/U dating, yield reproducible ages for each
marae
, and have a mean uncertainty of 9 y (2σ). Of 41 corals from wetter inland sites, 12 show some diagenesis and may yield unreliable ages; however, the majority (32) of inland dates are considered accurate. We also obtained six
14
C dates on charcoal from four
marae
. The dates indicate that temple architecture on Mo‘orea Island developed rapidly over a period of approximately 140 y (
ca.
AD 1620–1760), with the largest coastal temples constructed immediately before initial European contact (AD 1767). The result of a seriation of architectural features corresponds closely with this chronology.
Acropora
coral veneers were superceded by cut-and-dressed
Porites
coral blocks on altar platforms, followed by development of multitier stepped altar platforms and use of pecked basalt stones associated with the late ‘Oro cult. This example demonstrates that elaboration of ritual architecture in complex societies may be surprisingly rapid.