There are three surviving versions (BHL 2868 b-d) of the legend of St Felix, the oldest of which (9th century) is contained in a codex in the Abbazia di Farfa.  According to the legend, St Felix, Bishop of Civitas Martana was decapitated in the forum of the city in the reign of the Emperors Diocletian and Maximian on the orders of the prefect Tarquinius.  Christians (among whom, according to local tradition, was St Faustinus) recovered the body and buried it near a church that stood on the site of the present church of San Felice.

Silvestro Nessi (referenced below) drew on an entry in the Legendary of Farfa (9th century) that refers to the translation of the presumed relics of St Felix to what became the Abbazia di San Felice di Giano in the diocese of Spoleto.  He also refers to a later version of this legend, in which Bishop John of Spoleto dedicated an altar at San Felice di Giano to St Felix, and suggested that the translation of the relics and the dedication of the altar would have happened at the same time.  As he pointed out:

1. ✴a bishop of Spoleto of this name is securely documented in ca. 500, a time close to the date of destruction of Civitas Martana; and
   

2. ✴in the legend (10th century) of St John Penariensis, a bishop of Spoleto who is also called John was killed during the occupation of Spoleto by the Goths (i.e. in 545-7).  This means: either that Bishop John I reigned for some 50 years; or that there were two bishops of this name in the first half of the 6th century. 
   

The crypt of San Felice di Giano still houses the sarcophagus of St Felix, which Silvestro Nessi dates to the middle of the 5th century.  The relics were, apparently, rediscovered in 1783: an inscription on a reliquary from Santa Maria Maggiore, Spello (now in the Pinacoteca there) records the translation of a relic of this saint to Spello at that time (see the page on St Felix of Spello).

San Felice Dossal (ca. 1250)

This dossal, which is the autograph work of the Maestro di San Felice di Giano, came from the Abbazia di San Felice, Giano dell' Umbria.  It was removed to the local gallery in 1922 and subsequently to the Galleria Nazionale, Perugia. 

In the centre of the dossal, Christ sits in judgment in a mandorla, with censing angels to the sides.  Full-length figures occupy two registers to each side:

1. ✴the top register contains figures of SS Andrew, Simon and Paul and the Virgin to the left; and SS John the Baptist, Peter, James and Philip to the right; and
   

2. ✴the middle register contains figures of prophets.
   

Tondi below the figure of Christ contain the Lamb of God and the symbols of the Evangelists, with scenes from the martyrdom of St Felix to the sides.