Suger von Saint-Denis
The earliest form of window tracery, typical of Gothic architecture before the early 13th century, is known as plate tracery because the individual lights (the glazed openings in the window) have the appearance of being cut out of a flat plate of masonry. Romanesque church windows were normally quite small, somewhat taller than wide and with a simple round-headed ('segmental') arch at the top. From around the 1140s, the pointed arch Gothic window (employed by Abbot Suger for the redesign of the choir at St Denis) started to take over.