What did people use to poison kings?

Historically, various substances were used to poison kings, including toxic plants, heavy metals, and even certain fungi. Common poisons included arsenic, which was often undetectable, and belladonna, a toxic herb. Poisons were sometimes disguised in food or drink to ensure the act went unnoticed. Additionally, the art of poisoning was often shrouded in secrecy, with elaborate methods developed to evade detection.