Indic Mitra is first attested in a 14th century BCE Mitanni inscription in which an Indo-Aryan king of Mitanni invokes the gods Mitra, Indra, Varuna, and the Nasatyas as guarantors of his sworn obligations.
ˈɪndɪk mˈɪtɹə ɪz fˈɜːst ɐtˈɛstᵻd ɪn ɐ fˈoːɹtiːnθ sˈɛntʃɚɹi bˌiːsˌiːˈiː mˈɪtæni ɪnskɹˈɪpʃən ɪnwˌɪtʃ ɐn ˈɪndoʊˈɑːɹɹɪən kˈɪŋ ʌv mˈɪtæni ɪnvˈoʊks ðə ɡˈɑːdz mˈɪtɹə, ˈɪndɹə, vɑːɹɹˈuːnə, ænd ðə nˈæsɐɾɪəz æz ɡˈæɹɐntˌoːɹz ʌv hɪz swˈoːɹn ˌɑːblɪɡˈeɪʃənz.