Table:
text: List of encyclicals of Pope Benedict XV
The encyclicals of Benedict XV
The encyclicals of Benedict XV
No_ Title_Latin Title_English_translation Subject Date_
1. Ad Beatissimi Apostolorum To the Chair of the Prince of the Apostles Appealing For Peace 1 November 1914
2. Humani Generis Redemptionem Redemption of the Human Race On Preaching the Word of God 15 June 1917
3. Quod Iam Diu  On the Future Peace Conference 1 December 1918
4. In Hac Tanta  On St. Boniface 14 May 1919
5. Paterno Iam Diu  On the Children of Central Europe 24 November 1919
6. Pacem, Dei Munus Pulcherrimum Peace, the Beautiful Gift of God On Peace and Christian Reconciliation 23 May 1920

Question: What is the single subject on May 23, 1920 in the list of Pope Benedict XV's encyclicals?