Wessex is often symbolised by a wyvern or dragon.
Both Henry of Huntingdon and Matthew of Westminster talk of a golden dragon being raised at the Battle of Burford in AD 752 by the West Saxons. The Bayeux Tapestry depicts a fallen golden dragon, as well as a red/golden/white dragon at the death of King Harold II, who was previously Earl of Wessex. However, dragon standards were in fairly wide use in Europe at the time, being derived from the ensign of the Roman cohort, and there is no evidence that it identified Wessex.
A panel of 18th century stained glass at Exeter Cathedral indicates that the association of a dragon with the kingdom of Wessex pre-dates the Victorians. Nevertheless, the association was popularised in the 19th century, particularly in the writings of E A Freeman. By the time of the grant of armorial bearings by the College of Arms to Somerset County Council in 1911, a (red) dragon had become the accepted heraldic emblem of the former kingdom. This precedent was followed in 1937 when Wiltshire County Council was granted arms. Two gold Wessex dragons were later granted as supporters to the arms of Dorset County Council in 1950.
In the British Army the wyvern has been used to represent Wessex: The 43rd (Wessex) Infantry Division adopted a formation sign consisting of a gold wyvern on a black background, and both the Wessex Brigade and Wessex Regiments used a cap badge featuring the heraldic beast.
When Sophie, Countess of Wessex was granted arms, the sinister supporter assigned was a blue wyvern, described by the College of Arms as "an heraldic beast which has long been associated with Wessex".
The Wessex Society have promoted the use of a flag, designed by William Crampton, which features an heraldic golden wyvern on a red background. This was added to the UK Flag Registry in May 2011.