David Hume — The History of England Vol.I. Part A. & Chap 1.11

The Kingdom Of Sussex The history of this kingdom, the smallest in the Heptarchy, is still more imperfect than that of Essex. Ælla, the founder of the monarchy, left the crown to his son Cissa, who is chiefly remarkable for his long reign of seventy-six years. During his time, the South Saxons fell almost into a total dependence on the kingdom of Wessex; and we scarcely know the names of the princes who were possessed of this titular sovereignty. Adelwalch, the last of them, was subdued in battle by Ceadwalla, king of Wessex, and was slain in the action; leaving two infant sons, who, falling into the hand of the conqueror, were murdered by him. The abbot of Bedford opposed the order for this execution; but could only prevail on Ceadwalla to suspend it till they should be baptized. Bercthun and Audhum, two noblemen of character, resisted some time the violence of the West Saxons; but their opposition served only to prolong the miseries of their country; and the subduing of this kingdom was the first step which the West Saxons made towards acquiring the sole monarchy of England.[*]          [* Brompton, p. 800.]