|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|
|7.|Spiritus Paraclitus|The Spirit, the Paraclete|On St. Jerome|15 September 1920|
|8.|Principi Apostolorum Petro|To Peter, Prince of the Apostles|On St. Ephram the Syrian|5 October 1920|
|9.|Annus Iam Plenus||On Children in Central Europe|1 December 1920|
|10.|Sacra Propediem||On the Third Order of St. Francis|6 January 1921|
|11.|In Praeclara Summorum||On Dante|30 April 1921|
|12.|Fausto Appetente Die||On St. Dominic|29 June 1921|

Question: what was the number of encyclopedias that had subjects relating specifically to children?
Answer: 2