The cause of Kenshin's death has been questioned throughout the years. The theory accepted by most scholars is that early sources record his deterioration of health condition, his complaints of pain in the chest "like an iron ball", and as "Kenshin Gunki" (1582) records "on the 9th day of the 3rd month he had a stomach ache in his toilet. This unfortunately persisted until the 13th day when he died". However, it is also speculated that he was victim of one of the most famous ninja assassinations, by a ninja concealed in the cesspool beneath the latrine at Kenshin's camp with a short spear or sword. The theories are not mutually exclusive — the assassin, if he existed, and was possibly sent by Nobunaga, might simply have fatally wounded an already-dying man. However, as his anticipation of own death is recorded in the death poem, the possibility of the assassination is less likely.