The word arsenic was adopted into Greek (using folk etymology) as arsenikon (ἀρσενικόν) – a neuter form of the Greek adjective arsenikos (ἀρσενικός), meaning "male", "virile". Latin-speakers adopted the Greek term as arsenicum, which in French ultimately became arsenic, whence the English word "arsenic" in Late Middle Ages.

 Arsenic is often referred to as the “king of poisons” and the “poison of kings” because of its potency and the discreetness, by which it could be administered, particularly with the intent of removing members of the ruling class during the Middle Ages (5^th–15^th C) and Renaissance (15^th and 16^th C). It was also a popular way to get rid of unwanted relatives or rivals.  In 1960, activation analyses at the Harwell Nuclear Research Laboratory of the University of Glascow, London of authenticated hairs of Napoleon Bonaparte taken immediately after his death confirmed Napoleon's chronic arsenic poisoning on the island of St. Helena.

 In 1984, the EPA determined that pesticides containing arsenic were not safe and two years later banned most inorganic arsenic pesticides.

 In the 1860s, arsenic was used in embalming fluid. It was eventually replaced with formaldehyde (still the most common today). In addition to formaldehyde, some funeral homes now offer green embalming, which involves using an embalming fluid made from non-toxic chemicals and essential oils.

 In 19th-century England people considered small doses of arsenic safe and used it for diverse products, from face powder to rat poison. The substance found its way into food, textiles, medicine, and other common goods, so its use in wallpaper was not considered unusual.

 Arsenic compounds are still used to make special glass, semi-conductors (gallium arsenide), some paints, dyes, metals, soaps, and drugs. 

Some interesting facts about arsenic:

• History: Arsenic was known to ancient people and was important in alchemy. The German friar Albertus Magnus is usually credited with discovering the element in 1250. 
• Toxicity: Arsenic is highly toxic, especially in its inorganic form. It can damage multiple organs, including the skin, nervous system, and immune system. Even low doses can be dangerous, as arsenic can cause genetic damage and cancer. 
• Forms: Arsenic has several forms, or allotropes, including metallic gray, yellow, and black. 
• Occurrence: Arsenic is found in the Earth's crust, but is rare in its free form. It's usually found in minerals like arsenopyrite, orpiment, and realgar. Arsenic is also naturally present in groundwater in some countries. 
• Uses: Arsenic compounds were used in early times in bronze to make it harder, as pigments, and in medicines. Today, it's used in metallurgical applications, such as in the manufacture of lead shot. 
• Isotopes: Arsenic has one stable isotope, arsenic-75, and at least 32 radioisotopes. 
• Smell: When heated, arsenic oxidizes and releases a smell similar to garlic. 
• Sublimation: At normal pressure, arsenic sublimes directly into vapor, like carbon dioxide. Liquid arsenic only forms under high pressure. 

Just the facts:

Arsenic Definition & Meaning - Merriam-Webster

Arsenic and Old Lace by Joseph Kesselring, is one of my favourite stage plays. Nice comic situation and lots of laughs. I also enjoyed the movie. Unfortunately a lot of its references are too dated for a younger audience so it is now very rarely performed..