Beside the towers lies a small chapel which was built before the year 1115. The chapel was originally the apse of a much larger church which no longer exists. The official maps of the tax office of the Papal State dating from 1720-29 show that the church was still standing at that time. The apse was probably saved because of the beautiful frescoes on its walls. A papal bull of 1115 attributes the church to the powerful and rich Benedictine monastery of San Pietro in Perugia.
Inside the chapel there are delicate frescoes painted between 1315 and 1319 by the artist Meo da Siena, a student of Giotto, and the main painter of Umbria between 1290 and 1330. He is well known to the art-historians and there are several of his paintings in the National Gallery of Perugia, in a museum in Frankfurt and in several churches in Umbria and Latium.
The frescos depict Christ on the cross, Our Lady with Child and 9 saints, all except two in life-size proportions. Below the Christ on the cross there is a Madonna with Child, Saint John the Baptist, who announces the coming of Christ, and Saint John the Evangelist, the author of the Apocalypse, who marks the end of everything. In Christian religious art the image of Christ is closely related to the sun and the two Saint Johns, one looking towards the future and the other looking towards the past, remind us of the importance of time for everybody’s life and for the rise and fall of empires and religions. Some art historians consider the two Saint Johns as a Christian version of the Roman God Janus who had two faces. Several churches in Italy that are named after Saint John are dedicated to both of them, like the basilica of Saint John in Rome. Some have been built where there was in antiquity a temple dedicated to Janus, like in San Giovanni Rotondo in Apulia.