According to legend, King Edward the Confessor gave some land to one of his men in return for slaying a wild boar that had infested the nearby Bernwood Forest. The man built himself a mansion on this land, and called it 'Boar-stall' (Anglo Saxon for 'Boar House') in memory of the slain beast. The man was also given a horn from the dead beast and the legend says that whomsoever shall possess the horn, shall be the lord of the manor of Boarstall.
It is certainly the case from manorial records of 1265 that the owner of the manor of Boarstall was the ceremonial keeper of the Bernwood Forest, suggesting a link with the earlier legend. Given the proximity of Boarstall to the king's palace at Brill it would appear that this legend certainly has some basis in fact.
In the Magna Britannia in 1806 it was noted that the current incumbent of the manor, Sir John Aubrey, was in possession of a large horn "of a dark brown colour, variegated and veined like tortoise-shell. It is two feet four inches in length, on the convex bend, the diameter of the larger end is three inches; at each end it is tipt with silver, gilt, and has a wreath of leather, by which it is hung about the neck".
The manor was fortified in 1315. In the English Civil War this was turned into a garrison by King Charles I who was in possession of the nearby town of Brill. When Brill fell in 1643, so did the garrison at Boarstall. However whereas the manor at Brill was destroyed in the fighting, the fortified manor at Boarstall was saved, and used as a garrison by John Hampden's men, from which they were easily able to attack Royalist Oxford, just eight miles away.
Having no further use for the manor in 1644, Hampden left it to go and fight elsewhere. The house was then taken back for the Royalists by Colonel Thomas Gage, whom it is said launched such heavy fire from his cannons against the house that the incumbent Lady Denham was forced to evacuate and steal away in disguise. Gage left a small garrison in place to defend the house.
In May 1645 the house was attacked again by the Parliamentarian forces, this time led by Sir Thomas Fairfax himself, though he was unsuccessful. The following year in 1646 Fairfax returned, and the house was surrendered to him on June 10th, after a siege of 18 hours.
All that remains of the original fortified house today is the gateway and turrets, though the more modern house that replaced it, called Boarstall Tower is owned by the National Trust because of its historical importance.
Ecclesiastically, Boarstall was originally a chapel of ease for nearby Oakley, and its tithes were granted by Empress Maud to St Frideswide's monastery in Oxford. The parish of Boarstall was formed in 1418. The original church was mainly demolished during the English Civil War, though a replacement was constructed out of funds provided by Lady Denham.