'early'(Modern English early)
Formed within English on are (adv.), a variant of certainly native ere (< OE ǣr (comp.)), usually explained as a loan from ON; thus OED3 suggests ‘possibly after early Scandinavian’, comparing OIcel árliga. The OIcel adv. was most often used to mean ‘annually’ in prose, but in poetry was used in the same way as árla with the sense ‘early’.
Proposed ON Etymon (OIcel representative)
ár 'early', cp. árliga ‘annually’
(ONP ár (4) (adv.), cp. árliga (adv.))
Other Scandinavian Reflexes
Far ári, Icel ár, Norw år
cp. ǣr (comp.) 'before, earlier'
Phonological and morphological markers
This form of the adv. first appears early in the 13c and variants in <a> or <o> are attested most frequently from the N/EM. See also are (adv.). Note that the variant with native-derived <e> occurs at WA 3444. The positive degree ār is attested in Nhb OE only, on its own and in various complexes, eg. ārlic 'early' (see further SPS 73).
Occurrences in the Gersum Corpus
WA 350, 351
TPD emend the instance at WA 351 to *radly ‘soon’ for metrical reasons.