Book excerpt: From the conversion of the emperor Constantine in the early fourth century, vast sums of money were spent on the building and sumptuous decoration of churches. The resulting works of art contain many of the greatest monuments of late antique and early medieval society. But how did such expenditure fit with Christ's message of poverty and simplicity? In attempting to answer that question, this 1998 study employs theories on the use of metaphor to show how physical beauty could stand for spiritual excellence. As well as explaining the evolving attitudes to sanctity, decorum and display in Roman and medieval society, detailed analysis is made of case studies of Latin biblical exegesis and gold-ground mosaics so as to counterpoint the contemporary use of gold as a Christian image in art and text.