Hereford was by no means the only see that suffered these changes. It was simply a unit in the great policy of welding together the churches of the several kingdoms into one whole, which had never been carried into effect till Theodore of Tarsus came to England. He was a Greek monk little known till the Pope elected to fill the vacant archbishopric of Canterbury. Only three bishops were left in the whole of England; of these two were rivals for the See of York, and the third had bought the See of London. The first thing that Theodore did after his arrival was to travel throughout the country. By consecrating new bishops and creating a thorough organisation, he acquired a complete understanding with the Church. He also instituted a system of synods, which he intended should meet annually to discuss the general welfare of the Church. This, however, seems to have fallen into disuse. In all, Theodore managed to divide England into a matter of fifteen dioceses, through the subdivision of the old dioceses. Truly a great achievement when we remember that the conversion of the English kingdoms mostly depended upon the good-will of their respective kings. Thus it came about that one king in each kingdom had one bishop, generally his chaplain at first, who took his title, not from a see, but from the people. He was either bishop of Mercia, or Northumbria, or some other large kingdom. As we have seen in the collision with Wilford, Theodore's policy did not suit every prelate's views. His influence, however, effected the installation of three bishops in Northumbria, four in Mercia, two in East Anglia, and two in Wessex. Kent already had two since 604. Thus the result was the complete conversion of England, effected by Theodore from about 673 to 688 A.D. Prior to the eighth century Hereford is known to have been the capital of the kingdom of Mercia, as it is now of Herefordshire, which is much reduced in size. From the years 765 to 791 Mercia was governed by King Offa. Apart from his connection with the Cathedral of Hereford, his reign must possess some interest to the collectors of coins. For though the die-sinker's art was practised in England as far back as the Roman occupation, and an indigenous coinage came into existence in the seventh century, it is not till this monarch's reign that genuine English coinage was properly in currency. It appears that Offa had to pay an annual tribute of 365 mancuses in coin to the Pope. As a mancus was equal to 30 pennies, the sum was a considerable one.