Porta Sant' Angelo, the western gate of the medieval city, is so called because a church dedicated to Sant'Angelo was situated closeby before it was demolished in 1600.
There was also a hospital nearby, of which no trace remains, like the church, as can be perceived from a law contained in the "Statum Interamnae", which ruled that all those passing through porta San Angelo carrying firewood, had to leave a part to the hospital of "Santo Angelo", paying in this way a sort of tax which acquired the value of solidarity.
It seems somewhat strange in this day and age that a gate was built to be used as a bridge, and that along a country lane below the level of the road, an old mill can be found. In fact, there is no corresponding stream. However, up to the 16th century, all around the western wall of Terni flowed the Serra creek, whose course was later deviated Into the river Nera, of which it was a tributary. In olden times, the Serra flowed into the main river, downstream of the city, which was therefore enclosed by the two rivers and precisely for this reason this orographic configuration took the name Interamna. Interamna, which for those who see Terni today is not easily explained but which has a precise origin. After the deviation of the creek, which today flows into the Nera east of the residential area, Porta Sant'Angelo no longer acted as a bridge and the mill remained without water.
From Porta Sant'Angelo to the city centre there was access to a fountain which served all the neighbourhood inside the walls, and which was made up of the west side of the two Rugoni and Amengoni districts. Walking along the road, it was possible to reach the church and convent of Madonna del Monumento, where the cemetery of Terni was realised and which, as defined by law, had to be built far from the town.
After restoration work performed towards the end of the last century, porta Sant Angelo was incorporated into a new square and under it, also using the vestiges of the old oil mill, botanical gardens were planted, which at present are in a state of abandonment. The castle walls which ran from porta Sant Angelo to encircle the passeggiata public gardens, were demolished at the beginning of the 1900s, except for a short stretch now incorporated in an underground car park.