Here is a fascinating webpage about Giordano Bruno’s memory system.
Frances Yates reconstructed Bruno’s mnemonic wheel based on his book De Umbris Idearum. De Umbris Idearum can be downloaded here. Unfortunately, I’ve only seen it available in Latin so haven’t been able to read it.
Bruno’s sytem has a few similarities with the Dominic System and the person-action-object (PAO) system, where different images can be combined to expand the image vocabulary:
In the first fixed ring the practitioner will assign a mythological or heroic figure to each letter. Bruno provides some examples : A Lycaon; B Deucalion; C Apollo; D Argos … (see De Umbris Idearum [PDF], pp. 107 ff). The letters of the second ring correspond to an action or a scene associated with each figure. The examples provided are: AA Lycaon at a banquet; BB Deucalion and pebbles; CC Apollo and Python; DD Argos and some cattle (ibid, p. 112). Thus rotating the first inner ring operates permutations between the figures and their action. Further permutation occurs when the third wheel is set in motion. It contains attributes or enseignes which can be easily passed from one figure to another. Bruno provides only four examples and leaves the rest to the imagination of his reader. These are : AAA, Lycaon at a banquet with a chain; BBB, Deucalion and pebbles with a headband; CCC, Apollo and Python with a baldric; DDD, Argos and some cattle with a hood. This way the systems makes it possible to create combinations of letters representing words, acronyms or syllables to be remembered by means of animated images mixing the attributes and accustomed actions of familiar mythological figures.
BAA: B Deucalion A at a banquet A with a chain
MAD: M Perseus A at a banquet D with a hood
CAD: C Apollo A at a banquet D with a hood
COD: C Apollo O and Proserpina D with a hood
“Deucalion at a banquet with a chain. Perseus at a banquet with a hood.” It isn’t exactly a PAO system, but it has a familiar sound. I hope I can eventually find a copy of De Umbris Idearum in English so I can read the entire description of Giordano Bruno’s technique.
The Seven Images of Mars
The First Image of Mars is a Man armoured and riding upon a Lion upon whose Helm a Vulture strikes with it’s beak. He is a Man of most ferocious appearance.
Second: A Man armed with Broad-Sword and Spear upon whose Helm is a form resembling a Chimaera from whose mouth shoot sparkling flames.
Third: One who casts sulphurous Fire with his right hand, having taken hold with his left of the neck of a Leopard which he rides against it’s will.
Fourth: A Man having in his right hand a Sword unsheathed and dripping with blood and in his left a human Head whose countenance is burnt as if by the sun.
Fifth: A Man of tawny colouring riding upon a Wolf, dressed in Red garments and bearing a heavy Sceptre of Iron.
Sixth: A ravished and very beautiful Virgin before a Man who turns away from her: they are together in an Ivory-White Chariot drawn by two Dog-Headed Apes.
Seventh: A Leopard and a Tiger fighting, on both sides are two helmeted men threatening each other with drawn Swords.
I believe the Mnemonic images described above can be found in English in On the Composition Of Images, Signs & Ideas.