The term Middle English literature refers to the literature written in the form of the English language known as Middle English, from the 12th century until the 1470s, when the Chancery Standard, a form of London-based English, became widespread and the printing press regularized the language. There are three main categories of Middle English Literature: Religious, Courtly love, and Arthurian, though much of Chaucer's work stands outside these. Among the many religious works are those in the Katherine Group and the writings of Julian of Norwich and Richard Rolle.