Peter Harbison examines biblical scenes and arcane visions from the imagination of the medieval stonemason, captured by photographer James Fraher

The Midlands – and Co Offaly in particular – were blessed in the pre-Norman period with the dual gift of imaginative stone sculptors and a quantity of easily-workable material on which they could practise their magic. The latter was a warm-coloured sandstone which was susceptible to deep carving without splitting, yet equally capable of having shallow tooling applied to it with great effect. The disadvantage of sandstone over limestone – the other great medieval building material – is that it can crumble over the centuries, but those who prized it from its bedding in the (as yet unlocalised) quarry or quarry knew how to choose a closely-grained rock which would firmly withstand the effects of Irish weather – and the acid rain of more recent centuries