Many historians regard Egbert, King of Wessex, as the first ruler of all England. The other Anglo-Saxon kingdoms accepted him as their overlord, making him a sort of unifying figure.

Egbert was born about 770, the son of Elmund, king of Kent. At this time, Wessex and Mercia were the two most powerful of the Anglo-Saxon Heptarchy. When Egbert was born, it was Mercia that was the dominant power, largely through the influence of its most famous king, Offa. Other than that, historians know little about his early life. This was not unusual in those days. Egbert is known to have been driven into exile as the result of a Wessex succession dispute in 789 and to have returned after a few years. In 802, Egbert succeeded Beorhtric, one of those who had chased him out of Wessex (Offa being the other), as king of that land. Right away, Egbert moved to make himself an independent ruler, removing Wessex from what had been an alliance headed by Mercia. He also led an army southwest, to conquer the region of Dumnonia, which is today Cornwall.

The history of Wessex contains many stories of commanding, unifying figures as kings. Egbert set about bringing the other kingdoms under his sway. He defeated King Beornwulf of Mercia at the Battle of Ellandun in 825, in what some sources describe as a titanic struggle. The Anglo-Saxon Chronicle entry for that year reads thus:

Egbert, king of the West-Saxons, and Beornwulf, king of Mercia, fought a battle at Wilton, in which Egbert gained the victory, but there was great slaughter on both sides.

Egbert followed through on this victory four years later when he conquered Mercia itself, after defeating King Wiglaf of Mercia in battle. In that year, 829, he was proclaimed Bretwalda, or ruler of all England. He had earlier conquered Kent, Northumbria, Surrey, Sussex, and even Wales.

Egbert is thought to have spent some of his time in exile visiting or even serving under the great Frankish king Charlemagne. Egbert married Redburga, a Frankish princess, who was said to Charlemagne's sister. Egbert and Redburga had a daughter and two sons.

Egbert is also known to have been at the head of an army fighting against Danish and Norwegian raiders. These invasions increased near the end of his reign, at one point facilitated by an alliance with Dumnonia. Egbert's forces lost one battle, at Carhampton, and won one, at Hingston Down. He also lost Mercia to a revolt.

Egbert died in 839; his oldest son, Æthelwulf, became King of Wessex.

Egbert is also spelled in some sources as Ecbert or Ecgberht.