Dating of the Texts in which Aquinas Uses the Expression actus essendiText no. 11

Entry 0369: Dating of the Texts in which Aquinas
Uses the Expression actus essendi 

Aquinas uses the expression actus essendi in the Disputed Questions on the Power of God (De potentia) only once, in question 7, article 2, ad 1.

 Text no. 11: Disputed questions De potentia, question 7, article 2, ad 1.

Scholars seem to have fixed the date of composition of De potentia. 

After returning to Italy in 1259, Aquinas first worked in Orvieto from 1261 to 1265, and then moved to Rome where he directed the Study House of the Dominican Order from 1265 to 1268. 

There seems to be very little doubt that it was during this period in Rome that Aquinas wrote the disputed questions De potentia.

Referring to this teaching activity of Aquinas in Rome, Torrell accordingly remarks that “the disputed questions De potentia are precisely situated in this period” (Jean-Pierre Torrell, Saint Thomas Aquinas: The Person and His Work - Volume 1, trans. Robert Royal [Washington. D.C.: The Catholic University of America Press, 2005], 161).

Weisheipl for his part comments that “De potentia is chronologically and speculatively the immediate predecessor of the first part of the theological Summa” (James A. Weisheipl, Friar Thomas D’Aquino: His Life, Thought, and Works, 2^nd ed. [Washington. D.C.: The Catholic University of America Press, 1983], 200). Aquinas wrote the Prima Pars of the Summa theologiae in Rome in the period between 1266 and 1268.

And concurring with this, Susan C. Selner-Wright begins the introduction of her translation of De potentia, question 3, by saying that “Thomas Aquinas wrote his Disputed Questions On the Power of God (Quaestiones disputatae De potentia Dei or De potentia) in Rome in 1265–66. It was begun, but probably not completed, before he began the first part of his most famous work, the Summa theologiae, also composed during this time in Rome” (Thomas Aquinas, On Creation: Quaestiones disputatae De potentia Dei-Q. 3, trans. S. C. Selner-Wright, [Washington. D.C.: The Catholic University of America Press, 2011], vii).