Adelphopoiesis

Adelphopoiesis, or adelphopoiia (from the Greek ἀδελφοποίησις/ἀδελφοποιία, derived from ἀδελφός, adelphos, lit. 'brother', and ποιέω, poieō, lit. 'I make', literally 'brother-making') is a ceremony practiced historically in Orthodox-Christian tradition to unite together two people of the same sex (normally men) in a church-recognized relationship analogous to siblinghood.

Such ceremonies can be found in the history of the Catholic Church until the 14th century and in the Eastern Orthodox Church until the early 20th century. Documented in Byzantine manuscripts from the ninth to the fifteenth centuries, prayers established participants as 'spiritual brothers' (pneumatikoi adelphoi) and contained references to sainted pairs, including most notably Saints Sergius and Bacchus as well as Saints Cosmas and Damian, who were famous for their friendship." In England, some scholars believe an adelphopoiesis may have also taken place between William Neville and John Clanvowe.

In the late twentieth century, the Christian tradition gained notoriety as the focus of controversy involving advocates and opponents of secular and religious legalization of same-sex relationships.