In past years the climate in Britain went through much colder periods than in the last century. One of these, from the mid fourteenth century to the nineteenth century is sometimes known as the "Little Ice Age".
During this period the Thames froze over many times and the ice was thick enough and lasted long enough for festivals to be held on the river. The climate was not the only reason for the ice covering. In those days the Thames was wider and shallower than today, making it easier for ice to form.
Although the first recorded fair did not take place until 1608, the river froze over before this and it is said that King Henry VIII travelled by sleigh on the Thames from central London to Greenwich.
Left is a picture of the Thames in 1677.
In 1814, during a frost fair, an elephant was led over the ice near Blackfriars Bridge. As time went on the climate became milder and the banks of the Thames were altered, meaning that the river did not freeze so easily.