When the Vikings invade England, Alfred is about to take his priesthood vows. However, his brother, King Æthelred of Wessex, summons him to his aid and Alfred leaves for battle, where he appears to be a great tactician. Æthelred dies shortly after Alfred marries the Mercian princess Aelhswith. Torn between following intellect or passion, Alfred at first refuses to succeed Æthelred and consummate his marriage, but is forced to accept kingship after the Danes attack again. Realising the weak position of Wessex, Alfred goes into negotiations with Guthrum, the Danish Viking leader of the Kingdom of East Anglia. Aelhswith on the other hand agrees to become Guthrum's hostage and they start to develop feelings for each other. Alfred has difficulty acting like a king, calling for obedience and egalitarianism in the Medieval society of three estates, which the fighting nobility does not appreciate. The cleric Asser warns him that he is too proud and later, the Danes defeat Alfred. The latter is forced to retreat to the fens of Somerset. Roger's bandits, who take Alfred in, are more loyal to Alfred than his noblemen. The nobles however, drop their regicide plans and support Alfred in the climactic Battle of Athelney. Roger sees that Alfred will need help and in the midst of battle, he arrives with monks, old men and peasant women, armed with clubs and pitchforks. Alfred defeats Guthrum, knocking him out, but decides to spare his life and forgives Aelhswith.
Producer Bernie Smith says he became interested in Alfred the Great after reading about him in Winston Churchill's History of the English Speaking Peoples. The film was announced in March 1964 as A King is Born. It was "suggested" by a novel by Eleanor Shipley Duckett from a script by James R. Webb, who had written How the West Was Won for Smith. Filming was to take place in Ireland, with MGM financing. However it took a number of years for the film to be made. Peter O'Toole was mentioned as a possible lead. In February 1967 the lead role was given to David Hemmings, who had just appeared in MGM's Blowup. Smith said he "wanted a director who had never done a historical. That way I knew we could minimise cliches and the possibility of someone simply repeating, imitating what went before." Clive Donner, then best known for What's New Pussycat? was hired in September 1967, while Michael Killanin became associate producer. Donner said he wanted to make the film "because of the inherent youth problem which is so close to our so-called youth revolt; turning the destructiveness of youth into constructiveness. Like so many students today, he advocated peace, but at the same time proclaimed violence in order to redo the world."
