纪录片《大英博物馆世界简史》 062希伯来星盘（2）（在线收听）

This week's programmes are about high-status objects, from all over the world, that belonged to the leaders and thinkers of around seven hundred years ago - objects that offer profound insights into the society that made them. We don't know exactly who owned the Hebrew astrolabe in today's programme, but it tells us a great deal about how Jewish and Islamic scholars revitalised science and astronomy by developing the inheritance of classical Greece and Rome. This instrument speaks of a great intellectual synthesis, and it can also tell us about a time when the three religions Christianity, Judaism and Islam all peacefully co-existed. There was, in fact, no religious synthesis, but the three faiths lived together in fruitful tension, and the friction between them made medieval Spain the intellectual powerhouse of Europe.

An astrolabe makes accessible in compact form the sum total of medieval astronomical lore. Like the latest developments today - of phone, web and particularly sat nav - this was a must-have technology, a demonstration that you were right on the cutting edge. There's a wonderfully funny and touching letter written by Chaucer to his ten-year-old son Lewis, who is obviously like techie boys in every generation, and is clamouring to get to grips with an astrolabe. As well as writing him a letter, Chaucer also wrote him a little instruction manual, telling the boy how to use the instrument, and warning him just how difficult he was going to find it. Although I suspect that, like most children today, little Lewis quickly left his father behind: