The window depicts a scene of Christ’s Crucifixion- the moment that a Roman solider on horseback, pierced Jesus’ body with a spear bringing a sudden flow of blood and water. The design is taken from a painting by Peter Paul Rubens entitled Le Coup de Lance (1620).
Peterhouse College Chapel was built whilst Matthew Wren was College Master, 1625–1634. In order to fund the new chapel Wren appealed to Friends of the Colleges, past members and personal acquaintances. An astonishing £2,365 was collected, although the actual cost of building exceeded this amount. The seven chapel windows were glazed in 1632 'Ornatus fenestrarum sacris histories depingendae' and cost £118. The work began in 1628 and the Chapel was finished in time for its dedication on 17 March 1632.
Under William Dowsing, the carved wooden angels on the Chapel roof and the statues were destroyed along with the six side stained glass windows, also glazed in 1632. Some fragments of old glass remained in the windows after the Civil War.
The Flemish stained glass which filled the east window is thought to have been removed and hidden during the Civil War, thus surviving until the present day.
--- text adapted from Stained Glass, Laudians and Puritans: The Case of Peterhouse College Chapel, Cambridge
showing the window