Why does The Economist appear every seventh day? The answer is because we, like you, still regulate our lives by a septimal law that Mesopotamian star-gazers framed, and local warlords imposed, more than 40 centuries ago. Our weekdays and weekends and weeks off, our dress-down Fridays, hectic Saturday nights, Sundays sacred or profane, and Monday-morning blues all have their origin in something that happened around 2350BC. Sargon I, King of Akkad, having conquered Ur and the other cities of Sumeria, then instituted a seven-day week, the first to be recorded.

Ur was probably using weeks, less formally, long before Sargon came marching in. The Sumerians were great innovators in matters of time. It is to them, ultimately, that we owe not only the week but also the 60-minute hour. Such things came easily to people who based their maths not on a decimal system but on a sexagesimal one.
To the Sumerians, ultimately, we owe not only the week but also the 60-minute hour

Why were these clever chaps, who went for 60 because it is divisible by 2, 3, 4, 5, 6, 10, 12, 15, 20 and 30, fascinated by stubbornly indivisible seven? In ancient Egypt and ancient China, ‘weeks