black death which swept through Europe in the mid 14th century was
spread via the trade routes.
It was caused by the bite of
fleas carried by rats, the disease reached Ireland in 1348, devastating
the population. It killed many people, others fearful of catching
it fled to England.
During this period severe restrictions
were placed on travel in an attempt to contain it. This led to widespread
labour shortages, and ultimately to shortages of food. It is estimated
that approximately one third of the population died during the outbreak.
See also The
Irish Famines. and the famine of 1741