THE monastery of St. Peter's, Monkwearmouth, founded 674, and St. Paul's, Jarrow, 681-2, is described by Bede, the most famous member of the community, as one monastery in two places. Bede also records that for the building of Monkwearmouth its founder, Benedict Biscop, imported workmen from Gaul to construct a stone church and monastic buildings 'in the Roman manner' and glaziers to glaze the windows of the church, porticus, and refectories. The building of the second foundation at Jarrow was by members of the Monkwearmouth community and no mention is made of foreign artisans. 1 Both parts of the monastery were destroyed in the Scandinavian raids on Northumbria c. 867, and were never refounded as monasteries in the pre-Conquest period. During the last ten years excavations on both sites have yielded evidence for the large scale and elaborate construction of the public buildings, as well as producing a quantity of plain and coloured window-glass sealed in the destruction levels of the buildings.During the 1969 excavations of the monastic site at Monkwearmouth, a complete quarry of window-glass was discovered (pi. wve). This quarry was lying in tht construction trench of the north wall of the Norman south range, at a point where, this wall cut through a Saxon building. A few other fragments of coloured SaxoK glass were found in this area, but this piece is remarkable not only for its intaci condition, but also because it is the first fragment of decorated window-glass from Monkwearmouth and Jarrow.The quarry, which is grozed on all three sides, is an obtuse-angled triangle (though possibly meant to be a right angle) and measures 82 mm. by 52 mm. by 60 mm. It varies in thickness from 2 mm. at the base to 3 mm. at the point of the triangle. The metal, which is bubbly and completely clear and unweathered, is light amber in colour with darker amber veining, a colour combination which, in transmitted light, gives the appearance of alabaster. I have noted elsewhere 2 this alabaster effect on glass fragments from these sites, where the metal is colourless glass with red veins and streaks, or colourless glass with bluish-green streaks. This new fragment is, however, further embellished by combed opaque white trails which have been marvered into the surface of the glass. Three rows of such trails survive,