The fourteenth century was a period of extraordinary architectural creativity, with ideas first tentatively explored in the late thirteenth century being taken forward in brilliantly fresh ways. Those fresh ways were initially most prominently expressed in window tracery. On the one hand the ogee double-curve encouraged a taste for complex curvilinearity. On the other hand, a preference for grid-like rectilinearity ultimately inspired by French prototypes, but developed in strikingly new ways, was to set the pattern for the rest of the Middle Ages. Timber engineering was developed in several prodigiously inventive directions, with the central octagon of Ely Cathedral and the roof of Westminster Palace hall representing the highest achievements. The Royal Office of Works was an important forcing ground for new talent, as seen at St Stephen’s Chapel in Westminster; many named architects were recorded as working under the Office’s aegis before taking their creativity onto projects elsewhere.