In the Middle Ages, the windows in the Oude Kerk were fully or partially glazed with stained glass, allowing light to illuminate the church space in countless sparkling colour variations. The three stained-glass windows on the left of the Lady Chapel are the only remaining windows from the pre-Reformation period. The two windows now being restored are in the east wall of the Lady Chapel. The left window shows Mary on her deathbed with the apostles around her. This window is also known as the Crabeth window, because it was made around 1555 by Gouda glass painter Dirck Crabeth (1504-1574). To the right of the Crabeth window is the second so-called ‘Burgemeestersglas’ (mayor’s window), which was made in the mid-eighteenth century. This stained glass window complements the mayor’s window in the south aisle. The window in the south aisle shows the coats of arms of the mayors who governed the city from 1578 on and was supplemented until 1757, when there was no more room. The second mayor’s window shows the coats of arms of the mayors from that time on until 1795; other glass panels show the coats of arms of aldermen from the 1803-1806 period.
Last spring, the cracks in the masonry were carefully closed and the stone around the round window (rose window) located above the second mayor’s window was restored. However, this was not a sustainable solution. Almost every decade a new crack appears at this spot; this is due to the differences in pressure on the walls. The church has had a plan drawn up for an alternative, sustainable solution that would prevent further damage to the paintings. This plan was made in close collaboration with experts associated with the Dutch Cultural Heritage Agency, the Bureau Monumenten en Archeologie of the City of Amsterdam and an expert team of restorers.
Last spring, first of all, the secondary glazing was taken down and removed. The stone grooves that held the stained glass panels were also removed. Next, the stained glass panels were taken down and handed over to the glazier. The stone of the window frames is being repaired by a stonemason. In the restoration studio, the stained-glass panels were stripped of their lead profiles and carefully cleaned. After cleaning, the individual panes were assessed and, if necessary, repaired, suppressed or replaced. Next, the panes were fitted into a lead profile and sealed with a flexible sealant. After repair, the panels will be replaced in a museum setup. This means a setup in which the panels can move along with any displacement of the window frames in the event of future subsidence. To prevent damage from vandalism and climate impact on the panes in the future, new secondary glazing panels will be installed.