1520s, "to recount, tell," from French relater "refer, report" (14c.) and directly from Latin relatus, used as past participle of referre "bring back, bear back" (see refer), from re- "back, again" + lātus "borne, carried" (see oblate (n.)).
The meaning "stand in some relation; have reference or respect" is from 1640s; transitive sense of "bring (something) into relation with (something else)" is from 1690s. Meaning "to establish a relation between" is from 1771. Sense of "to feel connected or sympathetic to" is attested from 1950, originally in psychology jargon. Related: Related; relating.