Definition of "theirselves"

Or would they have it believed, that there is in their ſelves ſome ſuperior ſanctity, ſome peculiar privilege, by which theſe things are lawful to them, which are unlawful to all the world beſides?

1776, Jeremy Bentham, “A Short Review of the Declaration”, in John Lind, An Anſwer to the Declaration of the American Congress‎, London: Thomas Cadell, page 121

Horace: "Look, Jasper! Do you supposed they disguised theirselves?"

1961, Bill Peet, One Hundred and One Dalmatians, Walt Disney Productions