June 28 is remembered today as the centennial of Gavrilo Princip leaving a sandwich bar in Sarajevo and putting a bullet into the heir to the conjoined Austro-Hungarian Empire, thus triggering a war unsurpassed in carnage and grimness, even by European standards. What has gone practically unnoticed is that this day also marks a more glorious occasion, when 750 years ago the English parliament ratified what was to all effects a constitutional monarchy. An ordinance devolving power from the king to conciliar control was approved by the assembly and Henry III, no doubt under the threat of deposition, affixed his seal to it on this date. Simon de Montfort was clearly ready to take initiatives further when he summoned representatives from boroughs at the next parliament, but the events of 1265 cut the experiment short. While Edward revived the Montfortian precedents to some degree, it was mostly downhill after that, culminating in the murderous tyranny of the Tudors who, oddly enough, seem more popular than ever today in England.