The Treaty of Wedmore is a 9th-century accord between Alfred the Great of Wessex and the Viking king Guthrum the Old. The only contemporary reference to this treaty, is that of a Welsh monk Asser in his biography of Alfred, (known as "Vita Ælfredi regis Angul Saxonum" or Life of Alfred). In it Asser describes how after Guthrum's defeat at the Battle of Edington, followed by his surrender some days later, he agreed to a peace treaty with Alfred. The treaty was conditional on Guthrum's being baptised, and also Guthrum and his army leaving Wessex.