Upon succeeding to the Throne, he seems to have established himself as a strong monarch. He was called Cybrdan or the 'Supreme Daniel' in the 'Life of St. Euddogwy' and is recorded as having conquered 'Alamannia' ie. Germany. This seems unlikely but may be a mistranscription of some other place such as 'Albania' meaning Albion, an old name for Britain. It is possible that, like other Breton monarchs, he wished his kingdoms to spread across both sides of the Channel and took control of part of south-west Britain. While he was away, Marchil Chillon seems to have invaded Broerec and Cornouaille. He certainly beseiged Nantes in 497. The family were unable to return to Brittany for some years and Daniel's sons, Budic and Macsen, were raised in Britain.

Records of Daniel date back to the 11th century. He could well be historic.