Warner then abandoned contemporary allegory in favour of historical novels about Ancient Greece and Rome, including "Imperial Caesar", for which he was awarded the 1960 James Tait Black Memorial Prize for fiction. "Imperial Caesar" was praised by John Davenport as "delightfully perceptive and funny", and by Storm Jameson as "brilliant, intelligent, continuously interesting. It has everything." "The Converts", a novel about Saint Augustine, reflected Warner's own increasing devotion to Christianity. He dedicated it to the Greek poet and diplomat George Seferis.