Professor David Abulafia's wonderful book The Great Sea covers so many topics. Today we talked about slavery. Until recently I hadn't been aware of the sheer scale of the enterprise. Slavers from the Barbary ports raided as far north as the coasts of England and Ireland. In the east the Mongols brought slaves to the Black Sea ports where they were taken by Italian merchants past Constantinople and on to Egypt. Or to Europe. The fates of the enslaved was incredibly varied - positions of respect and power as part of a slave army, eunuchs in the harems, working in households, in the harem, short and brutal existences in quarries or on galleys. It is a remarkable subject and fascinating despite the horror.