Origin of -ize
Some words ending in -ize have been widely disapproved in recent years, particularly finalize (first attested in the early 1920s) and prioritize (around 1970). Such words are most often criticized when they become, as did these two, vogue terms, suddenly heard and seen everywhere, especially in the context of advertising, commerce, education, or government—forces claimed by some to have a corrupting influence upon the language. The criticism has fairly effectively suppressed the use of finalize and prioritize in belletristic writing, but the words are fully standard and occur regularly in all varieties of speech and writing, especially the more formal types.
The British spelling, -ise, is becoming less common in British English, especially in technical or formal writing, chiefly because some influential British publishers advocate or have adopted the American form -ize.
suffix forming verbs
Word Origin for -ize
word-forming element used to make verbs, Middle English -isen, from Old French -iser, from Late Latin -izare, from Greek -izein.
English picked up the French form, but partially reverted to the correct Greek -z- spelling from late 16c. In Britain, despite the opposition (at least formerly) of OED, Encyclopaedia Britannica, the "Times of London," and Fowler, -ise remains dominant. Fowler thinks this is to avoid the difficulty of remembering the short list of common words not from Greek which must be spelled with an -s- (e.g. advertise, devise, surprise).