The common design foreshadowed the unification of England over the next sixty years and the reform coinage[a] of King Edgar a century later.

Æthelred's grandfather, Ecgberht, became king of Wessex in 802, and in the view of the historian Richard Abels, it must have seemed very unlikely to contemporaries that he would establish a lasting dynasty.

No ancestor of Ecgberht had been a king of Wessex since Ceawlin in the late sixth century, but he was believed to be a paternal descendant of Cerdic, the founder of the West Saxon dynasty.

The Midland kingdom of Mercia dominated southern England, but its supremacy came to an end in 825 when it was decisively defeated by Ecgberht at the Battle of Ellendun.

By 830, Essex, Surrey and Sussex had also submitted to Ecgberht, and he had appointed Æthelwulf to rule the south-eastern territories as King of Kent.

[11] Ecgberht and Æthelwulf might not have intended a permanent union between Wessex and Kent as they both appointed sons as underkings and charters in Wessex were attested (witnessed) by West Saxon magnates, while Kentish charters were witnessed by the Kentish elite; both kings kept overall control and the underkings were not allowed to issue their own coinage.

[13] In 851 Æthelwulf and his second son Æthelbald defeated the Vikings at the Battle of Aclea and, according to the Anglo-Saxon Chronicle, "there made the greatest slaughter of a heathen raiding-army that we have heard tell of up to this present day, and there took the victory".

Historians do not believe that he was consecrated king at this young age and the real nature of the ceremony is explained in an extract from a letter of Pope Leo IV to Æthelwulf, which records that he decorated Alfred "as a spiritual son, with the dignity of the belt and the vestments of the consulate, as is customary with Roman consuls".

The contemporary Liber Vitae (confraternity book) of San Salvatore, Brescia, records the names of both Æthelred and Alfred, indicating that both brothers went to Rome.

The name of Æthelred's wife is only known because she was recorded as a witness to one charter, S 340 of 868, where she is shown as Wulfthryth regina, suggesting that she had a higher status than other kings' wives.

When Æthelbald died in 860, Æthelred and Alfred, who were still young, agreed to entrust their share to the new king, Æthelberht, on a promise that he would return it to them intact.

When Æthelred succeeded to the throne, Alfred asked him at a meeting of the witan (assembly of leading men) to give him his share of the property.

Some historians see the bequest as including the whole of Æthelwulf's bookland, his personal property which he could leave in his will (as opposed to the folkland which passed according to customary law and property earmarked for the support of the crown); it is further argued that it was considered desirable that the bookland would be kept by the king, so Æthelwulf's provision implies that the throne would pass to each brother in turn.

The historian Pauline Stafford suggests that Æthelred chose to highlight his wife's status as queen in a charter to assert his own sons' claims to the succession.

He is called by his father's usual title, Rex Occidentalium Saxonum (King of the West Saxons) in the charter of Ealhswith which he witnessed, and in five of his own.

[23][e] The West Saxon charters of Æthelred and his elder brothers followed a uniform style, suggesting that they were produced by a single agency which operated over a number of years.

Æthelred and Alfred led a large West Saxon army to Nottingham and besieged the Vikings, but they refused to leave the safety of the town's defences.

The combined Mercian and West Saxon armies were unable to breach the earth ramparts and ditch, and eventually Burgred bought them off.

Three days after their arrival they sent out a large foraging party, which was defeated by an army of local levies under the command of Æthelwulf, Ealdorman of Berkshire, at the Battle of Englefield.

After another four days, on about 4 January 871, Æthelred and Alfred brought up the main West Saxon army and joined Æthelwulf's forces for an attack on the Danes in the Battle of Reading.

[39] According to the twelfth-century chronicler Gaimar, Æthelred and Alfred only escaped due to their better knowledge of the local terrain, which allowed them to lose their pursuers by fording the River Loddon at Twyford and going on to Whistley Green, which is around 6 miles (9.7 kilometres) east of Reading.

[48] The historian and numismatist Rory Naismith comments that Æthelred: took the important step of adopting a new coin-type based not on local tradition, but on the Lunettes-type current in contemporary Mercia.

[49]Lyons and Mackay see the change as even more crucial: The developments of the late 860s can thus be viewed as an essential precursor that eventually led to the unified reform coinage of Edgar.

[a] This convergence of the coinage is also tangible evidence for a growing collaboration between Mercia and Wessex which foreshadowed the eventual creation of a unified England.

[51]The single coinage design created a form of monetary union in southern England, reinforcing the mingling of economic interests between the two kingdoms and the military alliance against the Vikings.

[54] There were also Irregular Lunettes issues, one of which was a degraded and crude variant, perhaps a result of a breakdown in controls at the end of Æthelred's reign, when Wessex was under the pressure of Viking attacks.

[63] Æthelred's descendants played an important role in governing the country in the late tenth and early eleventh centuries.