Some months back I posted with exuberance the appearance of two digitized manuscripts in the Vatican Library collection of Thomas Aquinas's autograph writings. Via twitter one of our readers (@annie3592) wondered whether Thomas might have been left-handed, given the slope of his writing. In response I told her that I had a memory of such a suggestion years ago when I was a paleography student in Toronto under Leonard Boyle, OP (shortly thereafter Prefect of the Vatican Library). Thompson, was the name? I had a visual memory of some folio volume, with a grayscale image on the left page, and the commentary on the right. But after years working with Marquette's paleography holdings I hadn't come across any book that triggered my memory. An upcoming manuscript research trip to Europe would be an opportune time to make the effort and put this one to bed. I just had to remember to hunt around in the libraries I visited.
Boom. In Berlin's German federal library recently (the Staatsbibliothek zu Berlin, or SBB) I was scanning through the stacks of manuscript catalogs and came across the book that brought it all back, S. Harrison Thomson's Latin Bookhands of Later Middle Ages 1100–1500 (Cambridge: CUP 1969). Skimming through it—1120's, 1150's, 1230's, 1240's—I came to rest on the familiar sight from thirty years ago. There, as item number 64, was a grayscale picture of the Vatican Library's autograph copy of the Summa contra gentiles (the corresponding color image of the autograph will be given below), plus Thomson's transcription and comments. Note: more comments after the pictures.
Here is the picture you can see by going to the Vatican Library website (f. 48r):
If you should take the time to read Thomson's grainy text (esp. towards the bottom of column 1) you'll find him saying something that had also stuck with me all these years:
"It has not, so far as I am aware, been pointed out that St. Thomas was writing with his left hand. It is not possible to approach an analysis of the script on any other assumption."
When I was with Father Boyle in Toronto (Spring term 1984) I took this comment to him, where he cast doubt on it; his explanation exceeded my then-minimal understanding of paleography, so I cannot reproduce his reasoning here. But there is one place where one would expect full-throated reasoning on Thomas's manner of writing, and that was Fr. Pierre-Marie Gils's article, "Saint Thomas, écrivain," found on pp. 173-209 as an appendix in vol. 50 of the Leonine edition of Thomas's Super Boetium De Trinitate. Expositio libri Boetii De ebdomadibus (the former work also being found in Vat. Lat. 9850), published in 1992.
So I grabbed the Staatsbibliothek's copy of Leonine vol. 50 and poured through "Saint Thomas écrivain." To my surprise, even consternation, Fr. Gils said nothing about the matter, and in an article replete with notes and documentation he made no reference to the entry in S. Harrison Thomson's Latin Bookhands. Of course Gils was a busy member of the Leonine Commission, and unless an entire article or book was devoted to Thomas's Super Boethium de trinitate it is unlikely that he would have taken the time to consider it. After all, is there any research more primary than helping to establish the primary source text from the autograph of the original author? Then again, maybe Fr Gils did know about Thomson's assertion, judged it wrong-headed, and chose to pass over it in charitable silence.
So this is where I am at the moment: I found the book in which a well-known scholar of medieval Latin manuscripts alleged Thomas's left-handedness (i.e., S. Harrison Thomson [1895-1975]), so it is possible to write at least that learned footnote. But now I need to accost someone who—as Reginald of Piperno himself sought—can read Thomas's hand with ease and insight, so as to settle the question in the native language of paleography.
Was Thomas a lefty? Can't say one way or the other right now.