Legal English the history of the development of English as a legal language. In prehistoric Britain, traditional common law was discussed in the vernacular (see Celtic law). The legal language and legal tradition changed with waves of conquerors over the following centuries. Roman Britain (after the conquest beginning in AD 43) followed Roman legal tradition, and its legal language was Latin. Following the Roman departure from Britain circa 410 and the Anglo-Saxon invasion of Britain, the dominant tradition was instead Anglo-Saxon law, which was discussed in the Germanic vernacular (Anglo-Saxon, Old English), and written in Old English since circa 600, beginning with
Anglo-Norman language of the language. By the late 15th century, however, what remained of insular French had become heavily anglicised: see Law French. It continued to be known as "Norman French" until the end of the 19th century even though, philologically, there was nothing Norman about it. One notable survival of influence on the political system is the use of certain Anglo-French set phrases in the Parliament of the United Kingdom for some endorsements to bills and the granting of Royal Assent to legislation. These set phrases include: The exact spelling of these phrases has varied over the years; for example, "s'avisera"