ENCYCLICALS AND OTHER WRITINGS OF PIUS IX

Theological

On Faith and Religion (Qui pluribus)
Promulgated  9 Nov 1846. Pius, upon assuming the pontificate, writes to the bishops concerning the errors of modern times concerning faith and religion. He speaks at length concerning the clergy, especially their education and duties.

On the Immaculate Conception (Ubi primum)
Promulgated 2 Feb 1849. Pius notes the requests from the Catholic world that the doctrine of the Immaculate Conception be infallibly defined, and that the conception of Mary receive further honor in the liturgy. He accedes to the latter and asks the bishops for their opinion on the former.

The Immaculate Conception (Ineffabilis Deus)
Apostolic Constitution issued by Pope Pius IX on December 8, 1854.

On Priests and the Care of Souls (Amantissimi Redemptoris)
Promulgated  3 May 1858. Pius speaks of the benefits of the Mass, and the obligation of offering and attending Mass He lays down a new ruling on when Mass must be offered.

On Promotion of False Doctrines (Quanto conficiamur moerore)
Promulgated 10 Aug 1863. Pius laments the attacks of unbelief, indifferentism and liberalism on the Church, and calls for renewed prayers.

Condemning Current Errors (Quanta Cura)
Promulgated 8 December 1864.

The Syllabus of Errors
Issued by Pope Pius IX in 1864 simultaneously with the Encyclical Quanta Cura. Covers errors of Pantheism, Naturalism, Indifferentism, Latitudinarianism, Socialism, Communism, also errors concerning civil society, the Church, natural and Christian ethics, Christian marriage, the Pope's civil power and modern Liberalism.