C14 wall projected but probably never built or never completed. (Bond)
Although the town was granted murage in 1322 (Cal. Pat. 1321-4, 42) there is no sign of fortification except for the park walls. There were bars at the town's entrances. Ale Bar gate on the Oxford road, recorded in 1504, was presumably the gate at the Town's End or Oxford gate referred to in C17. (Boro. Mun. 83/1 p 43; ibid. 79, ff. 171v.-172) In the early C16 there were bars on the east side of the town, (P.R.O., E 134/25 Eliz. I/Hil. 4) one probably on the present Hensington Road, another near the north end of Common Acre, barring the lane called Hensington Way or the way to Banbury. (Ibid.; Magd. Coll. Mun., Woodstock deeds no. 2; above, Intro) In 1583 it was recalled that the townsmen had received Henry VIII at Castle Hill, (P.R.O., E 134/25 Eliz. I/Hil. 4) apparently at the north end of Common Acre. In 1436 a toft and croft at the north end of Oxford Street extended eastwards to 'Castle Wall', (Magd. Coll. Mun., Woodstock deeds no. 2, of which missing words are supplied by ibid. EP 110/35) and a street, possibly the later Upper Brook Hill, leading to the same feature was mentioned c. 1461; (Boro. Mun. 83/1 p 4) there was apparently a small earthwork near the north end of Union Street in C19. (O.S. Map ½, 500, Oxon. XXVI. 8 (1876 edn.)) The nature of the 'castle' is unknown: an adulterine castle said to have been built at Woodstock by the Empress Maud may have been merely a fortification of the king's houses in the park. (Blenheim Mun., plans in wooden chest.) (VCH)
There are cases where 'murage' was clearly for earthen banks and ditches rather than stone walls but in this case it may well be the surtax was just levied to repair/replace the town gates and for some other unspecified civic improvements. Map reference for parish church.