proceeded to King Æthelberht's main town of Canterbury. He had been the prior of a monastery in Rome when Pope Gregory the Great chose him in 595 to lead the Gregorian mission to Britain to Christianise the Kingdom of Kent from their native Anglo-Saxon paganism. Kent was probably chosen because Æthelberht had married a Christian princess, Bertha, daughter of Charibert I the king of Paris, who was expected to exert some influence over her husband. Æthelberht was converted to Christianity, churches were established, and wider-scale conversion to Christianity began in the kingdom. Æthelberht's law for Kent, the earliest written code in any Germanic language, instituted a complex system of fines. Kent was rich, with strong trade ties to the continent, and Æthelberht may have instituted royal control over trade. For the first time following the Anglo-Saxon invasion, coins began circulating in Kent during his reign. In 635 Aidan, an Irish monk from Iona, chose the Isle of Lindisfarne to establish a monastery which was close to King Oswald's main fortress of Bamburgh. He had been at the monastery in Iona when Oswald asked to be sent a mission to Christianise the Kingdom of Northumbria from their native Anglo-Saxon paganism. Oswald had probably chosen Iona because after his father had been killed he had fled into south-west Scotland and had encountered Christianity, and had returned determined to make Northumbria Christian. Aidan achieved great success in spreading the Christian faith, and since Aidan could not speak English and Oswald had learned Irish during his exile, Oswald acted as Aidan's interpreter when the latter was preaching. Later, Northumberland's patron saint, Saint Cuthbert, was an abbot of the monastery, and then Bishop of Lindisfarne. An anonymous life of Cuthbert written at Lindisfarne is the oldest extant piece of English historical writing, and in his memory a gospel (known as the St Cuthbert Gospel) was placed in his coffin. The decorated leather bookbinding is the oldest intact European binding. In 664, the Synod of Whitby was convened and established Roman practice as opposed to Irish practice (in style of tonsure and dates of Easter) as the norm in Northumbria, and thus "brought the Northumbrian church into the mainstream of Roman culture." The episcopal seat of Northumbria was transferred from Lindisfarne to York. Wilfrid, chief advocate for the Roman position, later became Bishop of Northumbria, while Colmán and the Ionan supporters, who did not change their