Oxfordshire, once part of the Anglo-Saxon kingdom of Mercia, has always been a wealthy county. Its landscapes vary from the chalk and beechwood Chiltern Hills in the south to the limestone uplands of the Cotswolds in the north-west, which give very fine building stone. The land supports arable and sheep farming, and is watered by the River Thames and its many tributaries. All this is reflected in the variety of its church buildings, architecture that...