Poison at the Piast court? The mystery of Stanisław and Janusz III's deaths

The deaths of the last Masovian dukes — Stanisław and Janusz III — from the early 16th century remain the greatest criminal mystery in Masovia's history. Both young brothers from a cadet line of the Piasts ruled the Masovian Duchy; their premature deaths sealed the end of the duchy's independence. Historians still debate whether they died of natural causes or were poisoned.