In the end, his military prowess persuaded Childebert to abandon the dispute and adopt Theudebert as his heir.
After relations between the Frankish kings had settled down, Theudebert found himself embroiled in the Gothic War started when the Byzantine Emperor Justinian I attempted to subdue the Ostrogoths in Italy.
The Frankish armies saw the Italian conflict as an opportunity for plunder and a chance to exert their own claims to northern Italy.
[4] Since the fall of the Roman Empire, the Frankish kings had always shown a certain deference to the Byzantine Emperor, but Theudebert rejected his status as an inferior leader: for example, he broke imperial custom by minting gold coins containing his own image.
Hitherto former Frankish kings had respected imperial convention and circulated gold coins with the image of the emperor.
As well as being renowned for his military prowess, Theudebert was lauded by contemporaries for his patronage of the Gallic (French) Church.