The round window (left), standing in the Northeast transept, dates from about 1178. It is called an oculus, which means ‘eye’. The great height and the exposure of this window resulted in the designer making a complicated three dimensional frame, like a space frame to hold this huge window, almost 20 feet in diameter, that has clearly stood the test of time – over 830 years. • With a diameter of almost 4.5m the South oculus is an internationally important early ferramenta (iron framework) structure which is believed to date from between 1178 and 1180. The corresponding frame for the North oculus no longer survives. •• In subject matter the two windows form a pair. The North oculus features the Old Covenant associated with the past and darkness. The New Covenant is illustrated on the South side, the side of light and salvation. An excellent Cathedral link on these windows can be found here. [Window Photo Credits: Aidan McRae Thomson: AMT1 AMT2]