The name Delbert is of Germanic origin, derived from the elements "dell" meaning valley and "bert" meaning bright or famous. It first appeared in the 8th century among the Franks and later spread to other Germanic tribes.

One of the earliest recorded instances of the name is found in the Annales Regni Francorum, a chronicle of Frankish history from the late 8th century, where a nobleman named Delbert is mentioned. The name also appears in various medieval German documents and records from the 9th to 13th centuries.

While not commonly found in ancient texts or religious scriptures, the name Delbert does have a few notable historical figures. One of the earliest was Delbert of Gascony, a 9th-century count and military leader who fought against the Viking invasions in Aquitaine.

In the 11th century, Delbert of Metz was a prominent Benedictine monk and scholar who wrote several theological treatises. A century later, Delbert von Hohenzollern was a German noble and crusader who participated in the Third Crusade under Emperor Frederick Barbarossa.

During the Renaissance, Delbert Gerhard was a German humanist and philosopher who lived from 1466 to 1537. He was known for his works on logic and metaphysics, and his influence on the development of Protestant theology.

In more recent times, Delbert Mann was an American film director born in 1920, best known for his work on movies such as Marty and Separate Tables. He won an Academy Award for Best Director for the 1955 film Marty.