The name Arnaldo originates from the Germanic languages and is a compound of the words "arn," meaning eagle, and "wald," meaning ruler or power. Its earliest roots can be traced back to the 8th century and the Frankish kingdoms of western Europe.

Arnaldo gained popularity during the Middle Ages, particularly in Spain, France, and Italy. In the 13th century, it appeared in historical records referencing Arnaldo da Villanova, a renowned physician, alchemist, and astrologer who served as a counselor to the kings of Aragon and Sicily.

One of the earliest and most notable bearers of the name was Arnaldo Brescia, an Italian scholar and religious reformer born around 1090. His fiery criticisms of the Catholic Church's worldly possessions and call for apostolic poverty led to his eventual excommunication and execution in 1155.

In the 14th century, Arnaldo Dante, an Italian jurist and professor of law at the University of Bologna, wrote influential works on Roman law and canonization procedures. He lived from around 1260 to 1320.

The Renaissance period saw the rise of Arnaldo Mussato, an Italian historian and statesman from Padua, born in 1261. He is considered one of the first Renaissance humanist writers and is best known for his tragedy "Ecerinis," which chronicled the tyrannical rule of Ezzelino da Romano.

In the 16th century, Arnaldo Fioravanti, an Italian architect and sculptor active in Rome and Naples from 1508 to 1580, designed several notable buildings, including the Church of San Giovanni dei Fiorentini in Rome.

Another prominent figure was Arnaldo Arrighetti, an Italian painter and engraver from Florence born in 1709. He was renowned for his religious paintings and frescoes adorning churches throughout Italy.