Aethelbert was king of Wessex. He was born around 835CE, brother of Aethelbald who became king in 856 (deposing their father Aethelwulf).
Aethlebald died in 860 and Aethelbert succeeded him. He was crowned at Kingston-Upon-Thames (where the public library displays his attributed arms), but died five years later, without issue.
Aethelbert also claimed the kingship of Kent during his lifetime.