The Middle English creole hypothesis is the concept that the English language is a creole, i.e. a language that developed from a pidgin. The vast differences between Old and Middle English have led some historical linguists to claim that the language underwent creolisation at around the time of the Norman Conquest.The theory was first proposed in 1977 by C. Bailey and K. Maroldt and has since found both supporters and detractors in the academic world. Different versions of the hypothesis refer to creolisation through contact between Old English and Norman French, between Old English and Old Norse, or between Old English and the British Celtic languages. Some versions of the hypothesis actually propose multiple creolization events, with later ones reinforcing and broadening simplifications