[3][4] Along with North Street Postern Tower, on the opposite bank, it was built to control access to the city by way of an iron chain which was stretched across the river to impose the payment of tolls[5] and from medieval times until the construction of Lendal Bridge in 1863 a ferry service crossed the river between the two towers.

In 1569 bulwarks were added to the city defences as protection against the rebel Earls of Northumberland and Westmorland and repairs to the tower were undertaken in 1584–85.

[8][3] Water was pumped in using either a windmill or a waterwheel but this proved problematic and within a few years it was replaced by a horse engine situated within the tower.

[3][9] The next major developments came in the 1750s with the installation of a Newcomen steam engine which was rebuilt to the designs of John Smeaton in the 1780s when further expansion to the building took place.

[13][14] Lendal Tower was originally a circular building of 28 feet (8.5 m) in diameter, with a rounded turret to house a wooden spiral staircase, to which a 17th–century rectangular extension on the south-east of the structure has been added.