[1] He was sponsored by the British Army in the rank of second lieutenant on a university cadetship whilst at Cambridge before being commissioned, on 23 July 1971, as an Ensign in the Grenadier Guards; his personal number was 486330.

Fra' Ludwig Hoffmann von Rumerstein was chosen as Lieutenant ad interim and presided over the Sovereign Council that annulled the decrees establishing the disciplinary procedures against Boeselager as well as the suspension of his membership in the Order.

[9] In April 2017, Archbishop Giovanni Angelo Becciu, the temporary papal delegate to the Order, instructed Festing not to travel to Rome for the election of his successor.

He wrote that many of the Order had "expressed their wish" that Festing not travel to Rome for the election as they felt his presence would "reopen wounds" and prevent a return to harmony.

[4] Festing suddenly collapsed after attending the profession of vows of Fra' Francis Vassallo, in Saint John's Co-Cathedral of Valletta on 4 November 2021.

[11] His funeral Mass took place on 3 December at Saint John's Co-Cathedral, presided over by cardinal Silvano Maria Tomasi and then he was buried in the crypt of that church next to his predecessors.