Granny may have had a blue-and-white tea-pot which we remember as children, but where did the idea come from, and the technology? The history of blue-and-white is fascinating. It began in Basra in Iraq, was adopted by the Mongols, for whom it was made in Ching-te Chen in China, and was re-adopted in the Middle East, where Chinese blue-and-white was widely collected and copied. It became a major item of trade with the Portuguese in the 16th century, and the Dutch in the 17th century: as a result the technology spread to Europe, where the ultimate expression of blue-and-white was to be found in the Delft factories.

James Allan is now retired, but was curator of the Islamic collection and Keeper of Eastern Art at the Ashmolean Museum, Oxford University, where he also set up an inter-faith exhibition service and taught Islamic art and architecture. He leads tours in the Middle East and has published numerous articles and books on Islamic art, the most recent being, The art and architecture of Twelver Shi'ism: Iraq, Iran and the Indian Subcontinent.