Morris tune from Sherborne, Gloucestershire. Although Sharp visited Simpson at Upton, near Didcot, then in Berkshire, now in Oxfordshire, he had previously lived at Sherborne, and was Sharp’s informant for the Sherborne morris dances.

In the linked abc file this is tune number X:3

Princess Royal was composed by Irish harper Turlough O’Carolan (1670-1738), who called it “Miss MacDermott, or The Princess Royal”.  The MacDermott princes traditionally presided at the inauguration of the kings of Connacht. Hence the reference to the “Princess Royal”.
William Shields adapted the tune for his song “The Arethusa,” in his opera The Lock and Key, performed in 1796. In the Cotswolds it is used as a solo morris dance from several different villages, and in Abingdon as a set dance. O’Carolan’s original composition is in the minor mode. Some of the versions found in the tradition, such as this, are in the major.

The tune published in Bacon’s A Handbook of Morris Dances, marked (CJS from George Simpson 1911) is the same as Cecil Sharp’s no 2569, collected from Henry Simpson at Upton (Oxfordshire) on 6 April 1911.