What is the origin of allyship?

Allyship “the status of being an advocate for the inclusion of a marginalized group of which the advocate is not a member” is a compound of the noun ally and the combining form -ship, the latter of which denotes condition, character, or skill. Ally derives via Anglo-French and Old French from the Latin verb alligāre “to bind to,” from ligāre “to bind.” Additional descendants of ligāre include alloy, league, liable, ligament, and oblige, all of which involve a link to or merger with another person, object, or entity. Latin alligāre became alier “to unite, combine, join (in kinship)” in Old French, and its derivative noun, alliiet, gained the sense of “relative.” From there, ally shifted in English to mean “friend, associate” and then developed the additional meaning of “supporter or member of an alliance.” Today, the term has developed a specific nuance: allies are not part of the group that they support but stand in solidarity with the group nonetheless. Allyship was first recorded in English in the late 1840s in the sense “the state of being associated with another or others for a common purpose,” a definition that differs from allyship’s current meaning.