The article covers the peculiarities of the organization of the altar space and choir in the Church of San Francesco in Foligno and the description of the sacred space in the “Revelations of Blessed Angela” recorded by a certain Franciscan Arnaldo in the early 14th century. The author deals with Saint Angela of Foligno, the history of the text of the “Revelations”, its translation into Russian by L.P. Karsavin in 1918, and various perspectives of its study. The church space in the text of the “Revelations” undoubtedly refers to the space of the church of the convent of San Francesco in Foligno (ca. 1256), with which Saint Angela was closely associated. It is her testimony that allows us to hypothesize that in the layout of the Church of San Francesco the choir was supposed to be in front of the altar, in the space of the naos. This is important since the Franciscan architecture in Umbria, imitating the layout of the main basilica in Assisi, apparently had exceptional conformity in the arrangement of the choir in the space of the apse. The presbytery area of the Basilica of San Francesco in Assisi, in its turn, repeated the design of the papal basilicas in Rome, where the altar was located in the middle of the cross-shaped layout, while the choir and throne of the pope were placed along the apse curve. The article reveals the difference between the rectangular apse of San Francesco in Foligno and polygonal apses in other Umbrian Franciscan churches (in Assisi, Orvieto, Todi, Spello, Sansepolcro, Citta di Castello, etc.). In addition, the Franciscan church in Foligno is examined in the artistic and architectural context of the city. The author argues that the striking difference of the interior of the Church of San Francesco in Foligno could be determined by the dynamics of the socio-political life of the city and its surrounding area, mainly due to the relationship between supporters of the pope and the emperor and involvement of the Franciscans in these events.