I.A. Horowitz writes in "All about chess" which may be a collection of his columns for the Saturday Review:

And he is speaking of the game versus Guila above:

"The winner of the following brilliant game is another Roman Catholic ecclesiast, Giocchino Cardinal Recci, later to become Pope Leo XIII. It was played in Perugia, about 1875, and was recorded by a famous theologian and chess fancier Maurice de la Taille."- pg. 183

So, John Pope fielded some discussion of His Holiness, Pope Benedict but you see, this is really a game for your collections of games by wellknown people.

I regret that the game seems not to be genuine, according to the meticulous Edward Winter http://www.chesshistory.com/winter/... :

3705. Popes (C.N.s 3696 & 3701)
Peter Anderberg (Harmstorf, Germany) reports that the game allegedly played by the future Pope Leo XIII in the mid-1870s was in fact published in the Deutsche Schachzeitung, May 1850, page 175, as having occurred between Shumov and von Jaenisch: 1 e4 e5 2 ♘f3 ♘c6 3 ♗c4 ♗c5 4 c3 ♘f6 5 d4 exd4 6 e5 d5 7 exf6 dxc4 8 ♕e2+ ♗e6 9 fxg7 ♖g8 10 cxd4 ♘xd4 11 ♘xd4 ♗xd4 12 ♕h5 ♕f6 13 O-O ♖xg7 14 ♕b5+ c6 15 ♕xb7 ♖xg2+ 16 ♔xg2 ♕g6+ 17 ♔h1 ♗d5+ 18 f3 ♗xf3+ 19 ♖xf3 ♕g1 mate.

When was the game first associated with the name of Pope Leo XIII?"

Indeed, Chessgames gives this game but says it was played in 1845, and White resigned one move before mate Shumov vs Jaenisch, 1845

<The Pope's Love of Chess

"It may not b e known that Leo XIII is an ardent lover of chess. He has been a constant player for over 30 years, and his skill in the game is anything but mediocre.

"His holiness' favorite opponent used to be Father Giulio, with whom he was in the habit of playing when he was Carrdinal Pecci. On being raised to the Pontifical throne he summoned Father Glulio from Florence, where he as then stationed, and gave him apartments in the Vatican.

"Father Giulio was said to combine rare mastery of the game with an exceedingly irascible temper. Sometimes during a game with his holiness he would burst out into an ungovernable fit of rage. On such occasions Leo XIII immediately interrupted the contest and proceeded to deliver a little homily on the virtues of Christian resignation and self control."> -- ROme Correspondence