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.