Paris Green (also known as emerald green): the arsenic-containing pigment

was initiated in Europe in the early 19th century. Impressionist and post-impressionist painters used different versions of the pigment to create their vivid masterpieces. This means that many museum pieces today contain the poison.

Read the articles here: https://www.ancient-origins.net/artifacts-ancient-writings/deadly-poison-medieval-books-0010299

Arsenic pigment can cause serious health problems and death