Lee Smeaton (@NavyReg1970) contacted me on Twitter asking if I could recommend a good source for identifying Henry VII sovereign type pennies. Well, the best general reference work on the period it covers is English Coins 1180-1551. This was compiled by the late Lord Stewartby and is based upon a lifetime study of hammered gold and silver coins.
Lee asked the question because of the coin pictured here, which is a Henry VII sovereign type penny of Durham. On the obverse King Henry is seated on a throne with only one pillar. On the reverse there is a mitre (the headdress of a bishop) above the shield of arms, which has a letter R to the left and a D to the right of the lower section.
The letters on the reverse stand for Richard of Durham. In 1494 the Bishop of Durham (John Shirwood) died and this led to the appointment of Richard Fox.
The coin is irregular in shape and the legends mostly flat but even though the central areas are worn the detail shows up sufficiently for a full ID.