because London was not part of Æthelberht's domain. Also, London remained a stronghold of paganism, as events after the death of Æthelberht revealed. London at that time was part of the Kingdom of Essex, which was ruled by Æthelberht's nephew Sæbert of Essex, who converted to Christianity in 604. The historian S. Brechter has suggested that the metropolitan see was indeed moved to London, and that it was only with the abandonment of London as a see after Æthelberht's death that Canterbury became the archiepiscopal see, contradicting Bede's version of events. The choice of London as Gregory's proposed southern archbishopric was probably due to his understanding of how Britain was administered under the Romans, when London was the principal city of the province. Along with the letter to Augustine, the returning missionaries brought a letter to Æthelberht that urged the king to act like the Roman Emperor Constantine I and force the conversion of his followers to Christianity. The king was also urged to destroy all pagan shrines. However, Gregory also wrote a letter to Mellitus, the Epistola ad Mellitum of July 601, in which the pope took a different tack in regards to pagan shrines, suggesting that they be cleansed of idols and converted to Christian use rather than destroyed; the pope compared the Anglo-Saxons to the ancient Israelites, a recurring theme in Gregory's writings. He also suggested that the Anglo-Saxons build small huts much like those built during the Jewish festival of Sukkot, to be used during the annual autumn slaughter festivals so as to gradually change the Anglo-Saxon pagan festivals into Christian ones. The historian R. A. Markus suggests that the reason for the conflicting advice is that the letter to Æthelberht was written first, and sent off with the returning missionaries. Markus argues that the pope, after thinking further about the circumstances of the mission in Britain, then sent a follow-up letter, the Epistolae ad Mellitum, to Mellitus, then en route to Canterbury, which contained new instructions. Markus sees this as a turning point in missionary history, in that forcible conversion gave way to persuasion. This traditional view that the Epistola represents a contradiction of the letter to Æthelberht has been challenged by George Demacopoulos who argues that the letter to Æthelberht was mainly meant to encourage the king in spiritual matters, while the Epistola was sent to deal with purely practical matters, and thus the