> How do we know that the peptides that were detected were actually from Vlad? Many people may have handled the letters over the years. The authors acknowledge

> How do we know that the peptides that were detected were actually from Vlad? Many people may have handled the letters over the years. The authors acknowledge that it's a possibility. But there are mitigating circumstances. From the article: "the Sibiu Archive was founded in 1465 and it has been officially operating since that year. So, the two well-preserved documents of 1475 immediately began to be stored in the city’s official archive."