River Thames Frost Fairs - Historical Background

Historical Background

One of the earliest accounts of the Thames freezing comes from AD 250, when it was frozen solid for nine weeks. As long ago as 923 the river was open to wheeled traffic for trade and the transport of goods for 13 weeks; in 1410, it lasted for 14 weeks.

The period from the mid-14th century to the 19th century in Europe is called the Little Ice Age because of the severity of the climate, especially the winters. In England, when the ice was thick enough and lasted long enough, Londoners would take to the river for travel, trade and entertainment, the latter eventually taking the form of public festivals and fairs.

However, the colder climate was not the only factor that allowed the river to freeze over in the city: the Thames was broader and shallower in the Middle Ages – it was yet to be embanked, meaning that it flowed more slowly. Moreover, old London Bridge, which carried a row of shops and houses on each side of its roadway, was supported on many closely spaced piers; these were protected by large timber casings which, over the years, were extended – causing a narrowing of the arches below the bridge, thus concentrating the water into swift-flowing torrents. In winter, large pieces of ice would lodge against these timber casings, gradually blocking the arches and acting like a dam for the river at ebb tide.