This is the major international professional organization in anthropology. It holds its major meetings every 5 years, in venues scattered around the world. Intercongresses are often held at the 2 1/2 year interval between each 5 year meeting. In August, 1948, IUAES was united, de facto, with the International Congress of Anthropological and Ethnological Sciences (ICAES), founded in 1934, which, in turn, had followed various anthropological congresses from 1865 onward. IUAES and ICAES were united de jure in 1968.
From the website of SAR:
SAR grew out of three groups of anthropologists studying religion. In 1997, the Anthropology of Religion Section (ARS) formed within AAA combining the Anthropology of Religion Interest Group within AAA, the Society for the Anthropology of Religion (an independent non-profit organization), and an informal group of anthropologists who were working separately toward the formation of a section. In January 2000, the name was changed to Society for the Anthropology of Religion (SAR), a new society with a different organization having the same name as one of the original founding groups.
From the Wenner-Gren website: The Wenner-Gren Foundation is committed to playing a leadership role in anthropology. We help anthropologists advance anthropological knowledge, build sustainable careers, and amplify the impact of anthropology within the wider world. We dedicate ourselves to broadening the conversation in anthropology to reflect the full diversity of the field.