Over a quarter of a century ago, Robert Fogel and Stanley Engerman rocked the world of modern slave studies. In their two-volume Time on the Cross (1974) they made bold to claim that slave ownership and the exploitation of slave labour power in the antebellum Old South had been some thirty-five per cent more profitable, man for man, unit of production for unit of production, than the exploitation of free labour in the North. This was of course not only academically shocking, but also politically shocking. In the world’s richest country, a country whose economic and spiritual life was based around the notion of profit-making, it was being argued that the war which had been represented by the Union as one for the freedom of the Old South from slavery had in fact been economically irrational. The claim was of course disputed, on technical academic grounds among others; it has not been and perhaps cannot ever be substantiated (Fogel and Engerman 1974, cf. M. Smith 1998). But it did none the less put the issue of the profitability of slave labour firmly at the centre of US slave studies once more – in a way that it never has been, and possibly never can be, at the centre of ancient Greek slave studies.2