The Castle of Leiria and its walled nucleus, ex-libris of the municipality, are located in a privileged location, marked by the junction of the River Lis with the River Lena.

Archaeological remains indicate that that hill will have been occupied for about five thousand years.

Leiria was conquered to the Muslims, in 1135, by D. Afonso Henriques, having its castle a complex architectural evolution, with elements of military nature (Torre de Menagem), civil (Paços Novos) and religious (Church of Nossa Senhora da Pena) .