The chief Roman ruler, at any rate during the later wars against the
invaders, was called Dux Britanniae, "the ruler of Britain." It
became the aim of the ablest kings to restore the power of this
officer, and to carry on his work, to rule and defend a united
country. And I will tell you briefly how the kings ruled and
defended Wales for more than five hundred years--how Maelgwn tried to
unite it, how Rhodri tried to prevent the attacks of Saxon and Dane,
how Howel gave it laws, and how Griffith tried to defend it against
England.

Between 400 and 450 Rome left Wales to look after itself. An able
family, called the House of Cunedda, took the power of the Dux
Britanniae, and they translated the title into Gwledig--"the ruler of
a gwlad (country)." Of this family Maelgwn Gwynedd is the most
famous. It was his work to try to unite all the smaller kings or
chiefs of Wales under his own power as "the island dragon." It was a
difficult thing to persuade them; they all wanted to be independent.
A legend shows that Maelgwn tried guile as well as force. The kings
met him at Aberdovey, and they all sat in their royal chairs on the
sands. And Maelgwn said: "Let him be king over all who can sit
longest on his chair as the tide comes in." But he had made his own
chair of birds' wings, and it floated erect when all the other chairs
had been thrown down. Before Maelgwn died of the yellow plague in
547, his strong arm had made Wales one united country, and had made
every corner of it Christian.

The new wave of nations, coming on as surely as the tide, began to
beat against Wales. The Picts came from the northern parts of
Britain, and Teutonic tribes swarmed across the eastern sea. The
Angles came to the Humber, and spread over the plains of the north