Strange to say, this is the only record which we have of any fortress-building by the invading Saxons. Until we come to the time of Alfred, there is hardly an allusion to any fortification in use in Saxon times.[23] It is mentioned in 571 that the Saxons took four towns (_tunas_) of the Britons, and the apparent allusion to sieges seems to show that these British towns had some kind of fortification. The three _chesters_, which were taken by the Saxons in 577, Gloucester, Cirencester, and Bath, prove that some Roman cities still kept their defences. In 755 the slaughter of Cynewulf, king of the West Saxons, by the etheling Cyneard, is told with unusual detail by the _Chronicle_. The king was slain in a _bur_ (bower, or isolated women's chamber[24]), the door of which he attempted to defend; but this _bur_ was itself enclosed in a _burh_, the gates of which were locked by the etheling who had killed the king, and were defended until they were forced by the king's avengers. Here it seems to be doubtful whether the _burh_ was a town or a private enclosure resembling a stable-yard of modern times. The description of the storming of York by the Danes in 867 shows that the Roman walls of that city were still preserved. These passages are the solitary instances of fortifications in England mentioned by the _Chronicle_ before the time of Alfred.[25] The invasions of the Danes led at last to a great fortifying epoch, which preserved our country from being totally overwhelmed by those northern immigrants. The little Saxon kingdom of Wessex was the germ of the British Empire. When Alfred came to the throne it had already absorbed the neighbouring kingdoms of Kent, Sussex, and Surrey, and the issue hanging in the balance was whether this small English state would survive the desolating flood of pagan barbarism which had already overwhelmed the sister kingdoms of the Midlands and the North. It was given to Alfred to raise again the fallen standard of Christendom and civilisation, and to establish an English kingdom on so sound a basis that when, in later centuries, it successively became the prey of the Dane and the Norman, the English polity survived both conquests. The wisdom, energy, and steadfastness of King Alfred and his children and grandchildren were amongst the most important of the many factors which have helped to build up the great empire of Britain.