From 1326 to 1554 Birkrigg, and the surrounding land lying between Bardsea, Aldingham, Gleaston and Urswick, came under the ownership of the Barons Harrington of Aldingham. Robert the Bruce had made raids down the Cumbrian coast into Furness in 1316 and 1322, so Edward II installed John Harrington as the 1st Baron Harrington of Aldingham. Barons and their tenants were required to provide military service to the King and, in the case of the Aldingham barony, defend the kingdom from further Scottish raids; the baron also acted as an advisor in Parliament and moved frequently in court circles. It is believed John Harrington began to build Gleaston Castle as the seat of the barony.

Over several generations the Barony rose in influence at Court and in national affairs; through marriage and reward the wealth of the barony grew steadily. Aldingham Barons were involved at Agincourt and in many of the battles of the Cousins' War (War of the Roses).

In 1461, a baby girl of six months became the 7th Baron(ess) Harrington of Aldingham, a wealthy heiress and ward of Elizabeth Woodville, wife of Yorkist king Edward IV. To keep the wealth in the family, Elizabeth arranged for Cecily to marry her son from her first marriage, Thomas Grey, and, as women could not sit in Parliament, Thomas took over the role of 7th Baron. Thomas is best remembered for his attempt to rescue the "two princes in the Tower" from the clutches of Richard III before their mysterious disappearnace.

Cecily's grandson, Henry Grey, was the 9th and last Baron Harrington. He married Frances Brandon, Henry VIII's niece. After conspiring to have their daughter, Lady Jane Grey, made Queen for nine days, he was executed in 1554 on the orders of Queen Mary and all his lands confiscated. Much of the land of the Barony, including Birkrigg, has remained Crown property to this day. Much of the 9th Baron's property in Devon and Cornwall forms part of the Duchy of Cornwall estates of Prince Charles. But, although legally still owned by the Queen, Birkrigg is administered by the Crown Estates. The Crown Estates make large annual profits, most being given to the Treasury, but a percentage is retained as the Civil List. Unfortunately, Birkrigg has no economic value and therefore no importance. Before 1974 it was leased to Ulverston Urban District Council as an amenity; by default, the lease was transferred in 1974 to South Lakeland District Council, which takes a minimal interest in the condition of the Common as it is not the owner.

It would have been in these medieval times that Commoners' Rights were given to tenants of the Barony. These commoners' rights still largely exist, although they carry no responsibility to maintain the Common.

The Common is therefore caught in limbo with no one group prepared to take responsibility for its deteriorating condition; in large areas it is returning to scrub which will eventually become woodland....