We have said that William's father was Robert, the sixth Duke of Normandy, so that William himself, being his immediate successor, was the seventh in the line. And as it is the design of these narratives not merely to amuse the reader with what is entertaining as a tale, but to impart substantial historical knowledge, we must prepare the way for the account of William's birth, by presenting a brief chronological view of the whole ducal line, extending from Rollo to William. We recommend to the reader to examine with special attention this brief account of William's ancestry, for the true causes which led to William's invasion of England can not be fully appreciated without thoroughly understanding certain important transactions in which some members of the family of his ancestors were concerned before he was born. This is particularly the case with the Lady Emma, who, as will be seen by the following summary, was the sister of the third duke in the line. The extraordinary and eventful history of her life is so intimately connected with the subsequent exploits of William, that it is necessary to relate it in full, and it becomes, accordingly, the subject of one of the subsequent chapters of this volume.
_Chronological History of the Norman Line._
It was about 870 that Rollo was banished from Norway, and a few years after that, at most, that he landed in France. It was not, however, until 912 that he concluded his treaty of peace with Charles, so as to be fully invested with the title of Duke of Normandy.
He was advanced in age at this time, and, after spending five years in settling the affairs of his realm, he resigned his dukedom into the hands of his son, that he might spend the remainder of his days in rest and peace. He died in 922, five years after his resignation.
William was Rollo's son. He began to reign, of course, five years before his father's death. He had a quiet and prosperous reign of about twenty-five years, but he was assassinated at last by a political enemy, in 942.
He was only ten years old when his father was assassinated. He became involved in long and arduous wars with the King of France, which compelled him to call in the aid of more Northmen from the Baltic. His new allies, in the end, gave him as much trouble as the old enemy, with whom they came to help William contend; and he found it very hard to get them away. He wanted, at length, to make peace with the French king, and to have them leave his dominions; but they said, "That was not what they came for."