From the Roman cognomen Martialis, which was derived from the name of the Roman god MARS. The name was borne by Marcus Valerius Martialis, now commonly known as Martial, a Roman poet of the 1st century.
Possibly related to Latin mas "male" (genitive maris). In Roman mythology Mars was the god of war, often equated with the Greek god Ares. This is also the name of the fourth planet in the solar system.