Alfred, however, still had to fight against fresh invasion by the
Danes, who continued to make descents upon the coast, and even sailed
up the Thames to take London. The English King constructed a superior
class of fast-sailing war vessels from designs made by himself. With
this fleet, which may be regarded as the beginning of the English
navy, he fought the enemy on their own element. He thus effectually
checked a series of invasions which, if they had continued, might have
reduced the country to barbarism.