Reconstructing the history of the holy door in the sanctuary of monte Sant'Angelo (Foggia, Italy)

The sanctuary of San Michele Arcangelo dates back to 493 AD and is listed in the UNESCO World Heritage. The door of the sanctuary is considered a "perpetual holy door". It is made of bronze panels covering a wooden structure, which was investigated in order to identify the tree species and the dating. The wooden structure is made mainly by oak with few elements of larch. The oak has been dated through radiocarbon analysis to the year 1385 AD ± 65, while the larch was dated through dendrochronology to the year 1689. None of the wooden elements corresponds to the original structure, but they are the result of different restoration works. The oldest intervention, dated around 1400 AD, is not mentioned in any documentation or source, while the recentest one, towards the half of 1700, is probably the consequence of the fire that damaged the door in that time.