I've been reading Gulliver's Travels(1726) and noticed almost all words that we commonly spell ending "-ic" are instead spelt "-ck" such as publick or politick.
Researching online I can't find any information about these spellings except that they are archaic or obsolete. These also don't seem to be the original spellings as they do not appear in Shakespeare.
Were these spellings popular in the 17/18th century? Was there a spelling reform which introduced them?