The Hungarian Pray Manuscript artist seems to be familiar with the shroud, and this is around 1192-1195.
Also, historians have speculated, and I think correctly, that what is now known as the Shroud of Turin was known to the Byzantines as the Holy Mandylion of Edessa that has a historical trail back to the 6th century but which disappeared (coincidentally) at the sack of Constantinople in 1204. Though the Mandylion is often thought of as an image of the face alone, there are certain oddities in the accounts that suggest it was a much larger cloth folded in fours until only the face was visible--and one commentator I think in the 900s even said that the whole BODY of the dead Christ was imprinted on it.
Seems is not for sure. Even given that, all that would tell you is that it existed around 1192. No evidence that it was any older.
historians have speculated...that what is now known as the Shroud of Turin was known to the Byzantines as the Holy Mandylion of Edessa that has a historical trail back to the 6th century but which disappeared (coincidentally) at the sack of Constantinople in 1204.
Historians speculated? Speculated as in "made an educated guess"? That doesn't constitute any proof at all. Spend any amount of time watching the History Channel and you'll quickly realize historians often speculate (often wrongly) all the time. Speculation isn't evidence in favor or against a proposition.