Officially, there is only one: Alfred the Great, who ruled from 871 until 899. Although he is referred to as ‘English’ – in that he was of Saxon descent – Alfred was never king of a united England. That honour went to his grandson, Aethelstan in AD 927.
If the search is expanded to cover monarchs from across Britain, there are a few more names to consider. The Danish prince Cnut (often spelt ‘Canute’), who became King in England in 1016, is often referred to as Cnut ‘the Great’ following the extension of his power to Denmark, Norway and parts of Sweden, although he was not English in the sense of ethnicity and background.
Further afield in Wales, two monarchs, Rhodri, the ninth-century King of Gwynedd, and Llywelyn, Prince of Gwynedd (1195-1240), were later given the epithet ‘Great’. However this title never appears to have been extended to a Scottish king.
Two kings of the first century were credited with ‘greatness’. The first was Cunobelinus, – immortalised by Shakespeare in his play Cymbeline – who was leader of the Catuvellauni and Trinovantes tribes and was described by a Roman historian as “Great King of the Britons”.
The second was Tiberius Claudius Togidubnus, a tribal leader who used the title ‘Great King in Britain’ on a Roman inscription preserved in Chichester.