The given name Arnulfo has its origins in the Germanic languages and dates back to the 7th century. It is derived from the Old Germanic elements "arn" meaning eagle and "wulf" meaning wolf, hence the name can be interpreted as "Eagle Wolf" or "Brave as an Eagle and Wolf".

In its earliest form, the name was spelled as "Arnulf" or "Arnulph". It gained popularity in the Frankish Empire, which covered modern day France, Germany, and parts of Italy and the Low Countries during the Middle Ages. The name was particularly common among the Carolingian dynasty, which ruled the Frankish Empire from the late 7th to the late 9th century.

One of the earliest and most notable historical figures to bear this name was Arnulf of Metz (c. 582 – 640 AD), a Frankish bishop and Duke of Austrasia. Another prominent bearer was Arnulf of Carinthia (850 – 899 AD), who became the King of East Francia and later the Holy Roman Emperor.

In the 11th century, the name appeared in various religious texts and chronicles. Arnulfo was the name of a Benedictine monk and chronicler from Milan, who wrote a history of his city in the early 11th century. Around the same time, Arnulfo di Milano was an influential Archbishop of Milan.

During the Middle Ages, the name Arnulfo spread across Europe, particularly in regions influenced by Germanic culture. Notable bearers include Arnulf I, Count of Flanders (c. 890 – 965 AD), a powerful nobleman in medieval Flanders; Arnulf II, Duke of Bavaria (c. 954 – 1032 AD), a member of the Luitpolding dynasty; and Arnulf of Chocques (c. 1040 – 1124 AD), a Flemish nobleman and crusader.

In later centuries, the name Arnulfo continued to be used, though with less frequency. Arnulfo de Bayona (c. 1330 – 1419) was a Spanish Franciscan friar and theologian, while Arnulfo Arias Madrid (1901 – 1988) was a Panamanian politician and three-time President of Panama.