Beyond the pale is an English expression for anything beyond the limits of the law or of accepted morality. The aforementioned ‘pale’, far from being a symbolic separator, at one time was a very real barrier: it separated the area of Ireland under English control from the (larger) part of the country where fierce Celts still held sway unopposed.
This Pale – also known as the English Pale – existed in the 14th and 15th centuries, and came to signify the entire area covered (a region with a radius of about 35 kilometres) rather than the barrier itself. The barrier consisted of a fortified ditch and a rampart, behind which the Anglo-Irish were constantly fearful of Gaelic incursions. One is reminded instictively of the Green Zone in Baghdad, or the separation wall in Israel… I found a nice map of the English Pale (with the 4 traditional provinces of Ireland) here
Other Pales at some point included the region around Calais, when that city in the North of France was held by the English; and the Pale of Settlement in the western part of Tsarist Russia – the only part of the Empire the Jews were allowed to settle their shtetls in.