Английский Этимологический словарь - petition (n.)

- early 14c., "a supplication or prayer, especially to a deity," from O.Fr. peticion, from L. petitionem (nom. petitio) "a request, solicitation," from petere "to require, seek." Meaning "formal written request to a superior (earthly)" is attested from 1450. The verb is 1607, from the noun.