The name Mastin is an English given name derived from the Old French word "mastin," which means "mastiff dog." This word can be traced back to the Latin "mansuetinus," meaning "tamed" or "domesticated." The name likely originated during the Middle Ages when mastiff dogs were popular as guard dogs and hunting companions among the European nobility.

In the 12th century, the name Mastin appeared in English records as a surname, indicating that it was used as a nickname or a descriptive name for someone who worked with or kept mastiff dogs. Over time, it transitioned into a given name, though its popularity has remained relatively low throughout history.

One of the earliest recorded instances of the name Mastin as a given name can be found in the 14th century English manuscript, "The Canterbury Tales" by Geoffrey Chaucer. In this literary work, a character named Mastin is mentioned, suggesting that the name was in use during that time period.

In the 16th century, a notable Englishman named Mastin Brock (c. 1530-1599) was a Member of Parliament and Sheriff of Wiltshire. He played a role in the political and legal affairs of the time.

Another historical figure with the name Mastin was Sir Mastin Lemon (1616-1668), an English politician and landowner who served as a Member of Parliament for Cornwall during the English Civil War era.

In the 18th century, Mastin Maddocks (1738-1819) was a Welsh-born Anglican clergyman and author who served as the Archdeacon of Dorset and wrote several religious works.

More recently, Mastin Kipp (1888-1944) was an American painter and printmaker known for his landscape and urban scenes, particularly those depicting New York City.

While the name Mastin has historically been uncommon, it has maintained a presence throughout the centuries, often associated with individuals from England and Wales. Its unique etymology and connection to the mastiff dog breed have contributed to its distinctive character as a given name.