[2] The early modern theory of allegory is discussed in Sir John Harington's Apology for Poetry (included in his translation of Ariosto's Orlando furioso, 1591).
[3] Perhaps the most famous example of a thorough and continuous allegorical work from the Renaissance is the six books of Edmund Spenser's The Faerie Queene.
In book 4, for example, Agape has three sons: Priamond (from one), Diamond (from two), and Telamond (from téleios, perfect, but emended by Jortin to 'Triamond' in his 1734 edition).
[4] Furthermore, since any triad may be an analogue of another, the three brothers could also be an allegory of the three worlds of man's soul: the vegetative, the sensitive, and the angelic".
And this is the principle from whence springeth & groweth the discipline of allegoricall sense' (translated by Pierre de la Primaudaye in The French Academie, London, 1618, p. 671).