Today while listening to " Septimus Heap, Book One: Magyk" by Angie Sage on CD with my son the word "erstwhile" caught my attention. It's not a word one comes across often, certainly not in American English (Angie Sage is British.) I thought it would be much older than it turned out to be.
Erstwhile adv. Some while ago, formerly. arch.
1569 SPENSER Sonn. ix. in Van der Noodt's Theatre for Worldlings, Which erstwhile [later edd. earst] so pleasaunt scent did yelde. 1584 R. SCOT Discov. Witchcr. III. xix. 56 They resist the truth erstwhile by them professed. 1599 SANDYS Europæ Spec. (1632) 184 Those very same minds, wherein they were erst-whiles enshrined with all devotion. 1624 GATAKER Transubst. 209 Which our adversarie also Earstwhiles confessed. 1662 GLANVILL Lux Orient. 180 Those thick and clammy vapours which erstwhile ascended in such vast measures..must..descend again. 1881 A. J. DUFFIELD Don Quix. II. 407 During that year the clouds erstwhile had withheld their dew from the earth. - Oxford English Dictionary