King Henry VII, Protector of the Order of St. John, 1505-1509
King Henry VIII, Protector of the Order of St. John, 1511-1540
Emperor Francis II/King Francis I, Protector of the Order of St. John, 1792-1806/1835
Emperor Paul I, Protector of the Order of St. John, 1798-1801
Emperor Alexander I, Protector of the Order of St. John, 1801 -1825
The Order from time to time appointed Protectors to the Order. This honour was bestowed on Monarchs. A Protector needed to be powerful patron, to have any purpose. The Order did not, nor could not subsist in the Protector.
The Order did not always have Protectors and the Protectorship of the Order was haphazard. For example, the Order bestowed that title on two Kings of England (Henry VII and Henry VIII were individually honoured in this way in 1505 and 1511 respectively). It was not a hereditary protectorship. The title was not passed down, but bestowed individually.
The bestowal of the title of Protector to Emperor Paul I, was a gift of the Order, and not part of the Convention establishing the Catholic Grand Priory of Russia 4th/15th January 1797. This provided the Czar with the same relationship with the Order as Francis II of Austria and the German Empire, who was also a designated Protector.
However additional to his Protectorship, the Order not only gave Emperor Paul I a Cross of Devotion, but additionally he was presented a Grand Cross and a Habit of the Order. The Convention was ratified in November 1797 under Grand Master Hompesch, along with an agreement that Commanderies could be established for those of the Greek religion (i.e. Orthodox). Thus there was no problem subsequently, in making Paul I the Order's Grand Master, as he was counted as a full member, and secondly for the Emperor as Grand Master in carrying out an agreement already undertaken, in the creation of Commanderies for Russian Nobles (these were subsequently styled as a Grand Priory). Emperor Alexander I, assumed the role of Protector of the Order after his father's murder in 1801, had left a power vacuum in the Order. Alexander was concerned to further good foreign relations and undertook to restore the Order to its previous constitution. There is evidence that the succeeding Czars considered themselves as Protectors to the Order.
There was of course, a protectorship by Monarchs over national groups of Knights, which by the very fact that monarchy was hereditary - so too, was such protectorship.