Etymology

Formally, this v. can simply be explained as a continuation of OE (ge-)bryttian 'divide, dispense, distribute' < PGmc *ƀrut- (zero grade of s.v. *ƀreutan-, cp OE brēotan ‘to kill; destroy’ (more frequent in the prefixed form ābrēotan), cognate with OIcel brjóta ‘to break, damage, wreck (etc.)' and possibly MHG briezen (thus de Vries, Mag., Orel, Kroonen, but cp. Seebold s.vv. breut-a- (1) and (2))), cp. OIcel brytja 'chop into pieces'. Together with britten (v.), some ON input on the later use has been suggested (so OED3, MED) on the grounds that the more literal sense of the OIcel better parallels at least some senses of the ME verbs than the metaphorically extended OE senses. While such input certainly is not necessary to explain the ME, it may be plausible given the circumstantial evidence from the gap in attestation between OE and late ME, where the v. occurs mostly in N and alliterative texts. 

PGmc Ancestor

*ƀrut-

Proposed ON Etymon (OIcel representative)

brytja 'chop into pieces'
(ONP brytja (vb.))

Other Scandinavian Reflexes

Far brytja, Icel brytja, Norw brytja

OE Cognate

(ge-)bryttian 'divide, dispense, distribute', cp. (ge)brytnian ‘distribute, give’

Phonological and morphological markers

Summary category

CC3c

Attestation

Attested early in OE, but not again until late ME with senses arguably closer to the OIcel, e.g. 'cut into pieces, slaughter'. 
OED3 also identifies the OE v. bryttað in Cynewulf's Elene, which does have the sense 'destroy' (cp. WA 2256), with this v. DOE, however, interprets it instead as an instance of brȳtan ‘to crush, grind; break into pieces; destroy’ (< PGmc *ƀraut-).

Occurrences in the Gersum Corpus

WA 2256, 2697

The D MS of WA has (closely related) variant readings bryt(t)ynd at 2256 and 2697; see further britten (v.).

Bibliography

MED britten (v.) , OED3 brit (v.1) , HTOED , HTOED , Dance britten, de Vries bryti, Mag brytja, Orel *ƀrutjōjanan, Kroonen *breutan-, DOE gebryttian, AEW brytt(i)an