Writers in 14th and 15th century England such as John Trevisa and Thomas Hoccleve translated or adapted him into English.
In 1281, at the Thirty-sixth Council of Paris, in which several differences between bishops and mendicant orders were arranged, he sided with the bishops against the regulars. Referring to this, a contemporary philosopher, Godfrey of Fontaines mentioned him as the most renowned theologian of the whole city (qui modo melior de totâ villâ in omnibus reputatur).
Philip III of France entrusted to him the education of his son, who later, in 1285, ascended the throne as Philip IV. When the new king, after his coronation at Reims, entered Paris, Giles gave the address of welcome in the name of the university, insisting on justice as the most important virtue of a king. (For the text, see Ossinger, in work cited below.)
After filling several important positions in his order he was elected superior-general in 1292. Three years later Pope Boniface VIII appointed him Archbishop of Bourges, France, although Jean de Savigny had already been designated for this see by Pope Celestine V. The French nobility protested on the ground that Colonna was an Italian, but his appointment was maintained and approved by the king.
He was present at the Council of Vienne (1311-1312) in which the Order of Knights Templars was suppressed.
In Holy Scripture and theology he wrote commentaries on the Hexaemeron, the Canticle of Canticles, and the Epistle to the Romans; several Opuscula and Quodlibeta, various treatises, and especially commentaries on Peter the Lombard's Four Books of Sentences.
In philosophy, besides commentaries on almost all the works of Aristotle, he wrote several special treatises. But his main work is the treatise De regimine principum, written for, and dedicated to, his pupil, Philip IV. It passed through many editions (the first, Augsburg, 1473) and was translated into several languages. The Roman edition of 1607 contains a life of Egidio. The work is divided into three books: the first treats of the individual conduct of the king, the nature of his true happiness, the choice and acquisition of virtues, and the ruling of passions; the second deals with family life and the relations with wife, children, and servants; the third considers the State, its origin, and the proper mode of governing in times of peace and war.
His pedagogical writings have been published in German by Kaufmann (Freiburg, 1904).
His attitude in the difficulties between Pope Boniface VIII and King Philip IV was long believed to have been favourable to the king. But it has been proved that he is the author of the treatise De potestate ecclesiasticâ, in which the rights of the pope are vindicated. The similarity between this treatise and the bull Unam Sanctam seems to support the view taken by some writers that he was the author of the bull.
He had already taken an active part in ending the discussions and controversies concerning the validity of Boniface's election to the papacy. In his treatise De renunciatione Papæ sive Apologia pro Bonifacio VIII he shows the legitimacy of Celestine's resignation and consequently of Boniface's election. In philosophy and theology he generally follows the opinions of his master, St. Thomas, whose works he quotes as scripta communia.
The Defensorium seu Correctorium corruptorii librorum Sancti Thomæ Acquinatis against the Franciscan William de la Mare of Oxford is by some attributed to him; but this remains uncertain. Nevertheless, on many points he holds independent views and abandons the Thomistic doctrine to follow the opinions of St. Augustine and of the Franciscan School. He even errs in asserting that, before the Fall, grace had not been given to Adam, an opinion which he wrongly attributes to St. Augustine.
Giles wrote a commentary on Guido Cavalcanti's philosophical love canzone "Donna me prega" (see Enrico Fenzi, La canzone d'amore di Guido Cavalcanti e i suoi antichi commenti, Melangolo, 1999).
For some time after this other opinions prevailed in the Augustinian Order. But as late as the seventeenth century should be mentioned Raffaello Bonherba (d. 1681) who wrote Disputationes totius philosophiæ … in quibus omnes philosophicæ inter D. Thomam et Scotum controversiæ principaliter cum doctrinâ nostri Ægidii Columnæ illustrantur (Palermo, 1645, 1671); and Augustino Arpe (d. 1704) who wrote Summa totius theologiæ Ægidii Columnæ (Bologna, 1701, and Genoa, 1704).
Federico Nicolò Gavardi (d. 1715), the most important interpreter of Colonna, composed Theologia exantiquata iuxta orthodoxam S. P. Augustini doctrinam ab Ægidio Columnâ doctoræ fundatissimo expositam … (6 vols. fol., Naples and Rome, 1683-1696); this work was abridged by Anselm Hörmannseder in his Hecatombe theologica (Presburg, 1737). Benignus Sichrowsky (d. 1737) wrote also Philosophia vindicata ad erroribus philosophorum gentilium iuxta doctrinam S. Augustini et B. Ægidii Columnæ (Nuremberg, 1701).