Researchers have identified L-shaped patterns of small burn holes; four similar patterns. These burn holes are often called the poker holes because some have speculated that the holes were created by someone thrusting a hot poker through the Shroud while it was folded in four: a test by fire" by early Christians to ascertain the Shroud's authenticity. There is no basis for such a claim.
Because there are four matched mirrored repetitions of the holes showing progressive levels of burn penetration so that each pattern has four burn marks or holes, it is certain, however, that the cloth was folded in half lengthwise and then widthwise when the burns were made.
It is more likely that the burns were caused by a thurifer accidentally spilling some granules of burning incense onto the Shroud. But this, too, is speculation.
The poker holes are significant because they can be seen in an illustration in the Hungarian Pray Manuscript found in the Budapest National Library. This codex was written and illustrated circa 1192 CE.
