In January 26th 1531, the Tagus River Estuary was hit by a strong earthquake, the intensity of which in Lisbon was, according to relevant authors, greater than that of the 1755 earthquake. It was cited by most of the European annalists of the time and was responsible for the destruction of structures, the loss of lives, and enormous panic, thus making it one of the most disastrous earthquakes in the history of Portugal.