whenas (adv., conj.)youdaoicibaDictYouDict[whenas 词源字典]
early 15c., from when + as.
Whenas in silks my Julia goes
Then, then (methinks) how sweetly flows
That liquefaction of her clothes.

[Robert Herrick (1591-1674)]
[whenas etymology, whenas origin, 英语词源]