The name Thiago is derived from the Greek name Theodoros, which means "gift of God." The name has its roots in ancient Greek culture and can be traced back to the 5th century BC.

The name Thiago is a variant of the Spanish name Tiago, which is a form of the name Santiago, meaning "Saint James." It is believed that the name was introduced to Spain by the Visigoths, a Germanic tribe that invaded the Iberian Peninsula in the 5th century AD.

One of the earliest recorded instances of the name Thiago can be found in the "Codex Calixtinus," a 12th-century manuscript that documents the life and miracles of St. James the Great. The name was also mentioned in various medieval texts and chronicles from the Iberian Peninsula.

Throughout history, there have been several notable individuals named Thiago. One of the earliest was Thiago of Seville, a 13th-century Spanish theologian and philosopher who wrote extensively on Aristotelian philosophy. Another notable figure was Thiago de Montemor, a 16th-century Portuguese composer and musician who served at the court of King John III.

In the 20th century, Thiago Braga (1924-2016) was a renowned Brazilian painter and sculptor known for his abstract and geometric works. Thiago Silva (born 1984) is a Brazilian professional footballer who has played for various clubs, including AC Milan and Paris Saint-Germain, and has represented the Brazilian national team.

Another notable Thiago is Thiago Alcântara (born 1991), a Spanish professional footballer who currently plays for Liverpool FC in the Premier League. He is the son of former Brazilian footballer Mazinho and has represented both the Spanish and Brazilian national teams.

The name Thiago has maintained its popularity over the centuries, particularly in Portuguese and Spanish-speaking countries, where it is often associated with a sense of strength, nobility, and divine favor.