Other encyclicals, such as those on Christian marriage (Arcanum divinae sapientiae, 10th February 1880), on the Rosary (Supremi apostolatus oficii, 1st September 1883, and Superiore anno, 5th September 1898), and on Freemasonry (Humanism genus, 20th April 1884), dealt with subjects on which his predecessor had been accustomed to pronounce allocutions, and were on similar lines.
He published two books on Freemasonry, Die drei altesten Kunsturkunden der Freimaurerbriiderschaft and Hohere Vergeistigung der echt iiberlieferten Grundsymbole der Freimaurerei, but his opinions drew upon him the opposition of the Masons.
Its nominal subject is freemasonry, but its real aim is to plead for a humane and charitable spirit in opposition to a narrow patriotism, an extravagant respect for rank, and exclusive devotion to any particular church.
Kilwinning is the traditional birthplace of Scottish freemasonry, the lodge, believed to have been founded by the foreign architects and masons who came to build the abbey, being regarded as the mother lodge in Scotland.
Several series of papers also, as, for example, on " The Retention of the Apocrypha," " Freemasonry " (1854), " Duelling " (1856) and The Relation between the Jews and the Christian Church " (1857 2nd ed., 1859), which originally appeared in the Kirchenzeitung, were afterwards printed in a separate form.