The name ”Maenza” could derive from the hero Magenzio of Etruscan origin, as told in the Aeneid, or it could be linked to the invasion by Germanic tribes who built a fort here, referring to the name of the city of Mainz (Mainz).
The city was born, in fact, just after the destruction of the ancient city of Pianura di Priverno when populations took refuge in the nearby hills.
The history of Maenza, like that of countless medieval villages, is closely interwoven with the events of the dominant feudal lords and the struggle between the papacy and the feudal lords for control of the area
The family which is most recorded in the history of Maenza is that of the Counts of Ceccano, amongst which there Berardo I (1204-1254) who built the magnificent Baronial Palace that was home to St. Thomas Aquinas. Right here at Maenza, as appears from the minutes of the canonization process, St. Thomas performed his first miracle.
A pope who was interested in Maenza in positive terms was Leo XIII (1878-1903), of the Pecci of Carpineto who at that time managed the fief. Pope Leo XIII used to spend long days in this area hunting and the Pecci owned a house with a garden at the entrance to the village (Palazzo Pecci, now the Town Hall).