Like London's other gates, Aldgate was "fortified with porticullises and chained" in 1377 due to concerns about potential attacks by the French.

Aldgate's defensive functions are known to have been tested twice. Firstly during the Great Rising in the summer of 1381 when thousands of insurgents from the surrounding region, assisted by sympathisers within and without, entered the City through Aldgate, unopposed. The second breach was during the Siege of London,