Dagobert I was born about 610/611 AD. as the son of Chlotarius II, King of Neustria and his second wife Bertrude. In 623 AD. when he was about 12 years old, he was proclaimed King of Austrasia by his father (under pressure from the Austrasian nobility). From then on his education was entrusted to Bishop Arnulf of Metz and the Hofmeier of the palace, Pippijn van Landen. 

Although he was still officially under the care of his father, there is evidence that Dagober wrestled from this influence at a young age. However, in some cases, such as his forced marriage to Gomatrude in 626 AD. he had to give in to his father. At a meeting in Clichy, following his marriage to Gomatrude, however, he claimed all Austrasia from his father: Brie, Champenoise and perhaps also Dantelin came into his possession. 

“There was a serious quarrel between Chlothar and his son Dagobert; for the latter demanded that all the lands belonging to the Kingdom of Austrasia should be subordinated to him, and Chlothar stoutly refused to comply and would concede nothing”.

Dagobert, was doubtlessly urged upon by Austrasians nobles. 

After mediation by a commission of twelve Frankish Lords, among whom bishop Arnulf of Metz, the Austrasians acquired “all that belonged to Austrasia”, whereas Chlothar kept “for himself the territory lying beyond the Loire and in Provence.

Dagobert I was a man of great intelligence, clever in counsel and deed. He reigned for 16 years and was at perpetual enmity with the English. He first ordered that much wealth from the Royal fisc be distributed as alms through the Churches of the Saints.

Upon the death of Clothar II in 629 AD. Dagobert wished to establish unity in the Frankish realm and the following year made expeditions into Neustria and Burgundy where he succeeded in securing recognition of his authority. Under him the Merovingian monarchy attained its culminating point.