The London of the middle of the 17th century was a city of narrow, dirty streets. The streets were so narrow that it was often possible for a person at a window on one side of the street to shake hands with a neighbour on the other side. There was little light and air. It is no wonder that epidemics were common. The greatest epidemic of the plague broke out in 1665. Every house in which there were sick people was shut up, and no one was allowed to go in or out, and the door of the house was marked with a red cross.
The following year the Great Fire took place. It broke out late on a Saturday night in a street not far from London Bridge. The summer had been dry, a hot east wind blew and the fire spread quickly. The Thames was covered with boats full of people. The fire burned for five days and destroyed the greater part of the city. But it did the city good, as it cleared away the old wooden houses and dirty, narrow streets. The old church of St. Paul was among the buildings destroyed by the fire. In its place Wren built the present St. Paul's Cathedral.
