of a motte and bailey type and was rebuilt in stone before 1200. Work on the cathedral precinct started in 1096. Within it was built a cathedral church, a fortified bishop's palace and other monastic buildings. The formation of the precinct turned a large part of the town into an unpopulated area of quarry pits and building yards. Early mediaeval Norwich grew into a cosmopolitan city and expanded around the waterfront and westwards along St. Benedict's Street. During the 12th century there was a thriving Jewish community, but it was unpopular with the Christian population. In 1144 the Jews were accused of the ritual murder of a young boy named William, who was subsequently canonized. Their synagogue was destroyed in 1286 and four years later all the Jews in England were expelled from the country (see Edict of Expulsion). Tensions between the cathedral priory and the citizens of Norwich (in part over the jurisdiction of land in the city) culminated in the Riot of 1272, in which thirteen members of the priory were murdered and the precinct gates and St. Ethelbert's Church were destroyed. As punishment, the main anarchists were put to death and the city lost its liberties and was forced to pay for the building of a new gate for the priory. Between 1297 and 1344 a new defensive wall was constructed on the huge banks that surrounded the city, replacing the earlier palisade and gates. The area enclosed was the largest for any city in England, although inside was a considerable amount of pasture land, which was slowly absorbed as new monastic settlements, houses, markets and industrial sites appeared. By 1400 Norwich had grown to become a major city of perhaps 10,000 inhabitants. The Black Death may have killed two fifths of the population of the city. It led to efforts to improve the unsanitary conditions, but these had little impact. Immigration from the surrounding countryside soon restored pre-plague numbers, partly as a result of the growing textiles industry. Growing civic wealth and pride was reflected in new large buildings such as the Guildhall, built from 1407 to 1453. During the later mediaeval period, Norwich's fortunes declined. Both the fires of 1412 and 1413 (which destroyed many of the city's buildings) and the Wars of the Roses, contributed to its decline. The period is characterised by a growing gap between the wealthy and the poor of Norwich.