“Time immemorial” has operated as a legal fiction in the discourse of colonization, performing a genealogical function in the construction of “antiquity” and “legal memory” in English law, and repurposed in Indigenous rights cases in Canada. Beginning with a genealogical outline, this paper analyzes “time immemorial” in relation to Settler and Indigenous discourses of time, memory and the land in Calder, Van der Peet, and Tsilhqot'in.