In 1988, three radiocarbon dating tests dated a corner piece of the shroud from the Middle Ages, between the years 12, which is consistent with the shroud's first known exhibition in France in 1357.
The image on the shroud is much clearer in black-and-white negative than in its natural sepia color, and this negative image was first observed in 1898 on the reverse photographic plate of amateur photographer Secondo Pia, who was allowed to photograph it while it was being exhibited.
The origins of the shroud and its images are the subject of intense debate among theologians, historians and other researchers.
Diverse arguments have been made in scientific and popular publications claiming to prove that the cloth is the authentic burial shroud of Jesus, based on disciplines ranging from chemistry to biology and medical forensics to optical image analysis.
The shroud is kept in the royal chapel of the Cathedral of Saint John the Baptist in Turin, northern Italy.