Describe the mayhem caused by the rats that had come with the ships. 

Along with the ships came rats carrying the deadly bubonic plague infection, the ‘Black Death’.

i. Western Europe, relatively isolated in earlier centuries, was hit by the epidemic between 1347 and 1350. The modern estimate of mortality in that epidemic is that 20 per cent of the people of the whole of Europe died, with some places losing as much as 40 percent of the population.

ii. As trade centres, cities were the hardest hit. In enclosed communities like monasteries and convents, when one individual contracted the plague, it was not long before everyone did. And in almost every case, none survived. The plague took its worst toll among infants, the young and the elderly.
iii. There were other relatively minor episodes of plague in the 1360s and 1370s. The population of Europe, 73 million in 1300, stood reduced to 45 million in 1400.