Wiki : Frost Fairs

The River Thames frost fairs were held on the tideway of the River Thames in London, England in some winters, starting at least as early as the late 7th century all the way until the early 19th century. Most were held between the early 17th and early 19th centuries during the period known as the Little Ice Age, when the river froze over most frequently. During that time the British winter was more severe than it is now, and the river was wider and slower, further impeded by the medieval Old London Bridge.