This article contains a list of encyclicals of Pope Leo XIII. Leo issued 85 Papal Encyclicals during his twenty-five year reign as Pope from 1878-1903.[1][2]
| No. | Title (Latin) | Title (English translation) | Subject | Date |
|---|---|---|---|---|
| 1. | Inscrutabili Dei Consilio | On the Evils of Society | 21 April 1878 | |
| 2. | Quod Apostolici Muneris | On Socialism | 28 December 1878 | |
| 3. | Aeterni Patris | Of the Eternal Father | On the Restoration of Christian Philosophy | 4 August 1879 |
| 4. | Arcanum divinae sapientia | The mystery of Divine Wisdom | On Christian Marriage | 10 February 1880 |
| 5. | Grande Munus | On Saints Cyril and Methodius | 30 September 1880 | |
| 6. | Sancta Dei Civitas | The Holy City of God | On Mission Societies | 3 December 1880 |
| 7. | Diuturnum | On the Origin of Civil Power | 29 June 1881 | |
| 8. | Licet Multa | On Catholics in Belgium | 3 August 1881 | |
| 9. | Etsi Nos | On Conditions in Italy | 15 February 1882 | |
| 10. | Auspicato Concessum | On St. Francis of Assisi | 17 September 1882 | |
| 11. | Cum Multa | With many | On Conditions in Spain | 8 December 1882 |
| 12. | Supremi Apostolatus Officio | The Supreme Apostolic Office | On Devotion to the Rosary | 1 September 1883 |
| 13. | Nobilissima Gallorum Gens | On the Religious Question in France | 8 February 1884 | |
| 14. | Humanum Genus | On Freemasonry | 20 April 1884 | |
| 15. | Superiore Anno | Last year | On the Recitation of the Rosary | 30 August 1884 |
| 16. | Immortale Dei | "Immortal God" | On the Christian Constitution of States | 1 November 1885 |
| 17. | Spectata Fides | On Christian Education | 27 November 1885 | |
| 18. | Quod Auctoritate | Proclaiming a Jubilee | 22 December 1885 | |
| 19. | Iampridem | On Catholicism in Germany | 6 January 1886 | |
| 20. | Quod Multum | On the Liberty of the Church | 22 August 1886 | |
| 21. | Pergrata | On the Church in Portugal | 14 September 1886 | |
| 22. | Vi È Ben Noto | On the Rosary and Public Life | 20 September 1887 | |
| 23. | Officio Sanctissimo | The Holiest Office (or Duty) | On the Church in Bavaria | 22 December 1887 |
| 24. | Quod Anniversarius | This Anniversiary | On His Sacerdotal Jubilee | 1 April 1888 |
| 25. | In Plurimis | On the Abolition of Slavery | 5 May 1888 | |
| 26. | Saepe Nos | On Boycotting in Ireland | 24 June 1888 | |
| 27. | Libertas praestantissimum donum | Liberty | On the Nature of Human Liberty | 20 June 1888 |
| 28. | Quam Aerumnosa | On Italian Immigrants | 10 December 1888 | |
| 29. | Etsi Cunctas | On the Church in Ireland | 21 December 1888 | |
| 30. | Exeunte Iam Anno | On Right Ordering of Christian Life | 25 December 1888 | |
| 31. | Magni Nobis | On The Catholic University of America | 7 March 1889 | |
| 32. | Quamquam Pluries | On Devotion to St. Joseph | 15 August 1889 | |
| 33. | Sapientiae Christianae | Of Christian Wisdom | On Christians as Citizens | 10 January 1890 |
| 34. | Dall'alto Dell'apostolico Seggio | On Freemasonry in Italy | 15 October 1890 | |
| 35. | Catholicae Ecclesiae | Of the Catholic Church | On Slavery in the Missions | 20 November 1890 |
| 36. | In Ipso | In itself | On Episcopal Reunions in Austria | 3 March 1891 |
| 37. | Rerum Novarum | "New Things" | On Capital and Labour | 15 May 1891 |
| 38. | Pastoralis | Of pastoral (things) | On Religious Union | 25 June 1891 |
| 39. | Pastoralis Officii | Of the Pastoral Office | On the Morality of Duelling | 12 September 1891 |
| 40. | Octobri Mense | The Month of October | On the Rosary | 22 September 1891 |
| 41. | Au Milieu Des Sollicitudes | On the Church and State in France | 16 February 1892 | |
| 42. | Quarto Abeunte Saeculo | On Christopher Columbus | 16 July 1892 | |
| 43. | Magnae Dei Matris | Of the great Mother of God | On the Rosary | 8 September 1892 |
| 44. | Custodi Di Quella Fede | On Freemasonry | 8 December 1892 | |
| 45. | Inimica vis | On Freemasonry | 8 December 1892 | |
| 46. | Ad Extremas | To the farthest | Seminaries for Native Clergy | 24 June 1893 |
| 47. | Constanti Hungarorum | On the Church in Hungary | 2 September 1893 | |
| 48. | Laetitiae Sanctae | Of holy praise | Commending Devotion to the Rosary | 8 September 1893 |
| 49. | Providentissimus Deus | The most provident God | On the Study of Holy Scripture | 18 November 1893 |
| 50. | Praeclara Gratulationis Publicae | The Reunion of Christendom | 20 June 1894 | |
| 51. | Litteras A Vobis | On the Clergy in Brazil | 2 July 1894 | |
| 52. | Iucunda Semper Expectatione | On the Rosary | 8 September 1894 | |
| 53. | Orientalium Dignitas | The dignity of the Easterners | On the Churches of the East | 30 November 1894 |
| 54. | Christi Nomen | The Name of Christ | On Propagation of the Faith and Eastern Churches | 24 December 1894 |
| 55. | Longinqua | On Catholicism in the United States | 6 January 1895 | |
| 56. | Permoti Nos | On Social Conditions in Belgium | 10 July 1895 | |
| 57. | Adiutricem | Adjutrix | On the Rosary | 5 September 1895 |
| 58. | Insignes | On the Hungarian Millennium | 1 May 1896 | |
| 59. | Satis Cognitum | On the Unity of the Church | 29 June 1896 | |
| 60. | Fidentem Piumque Animum | On the Rosary | 20 September 1896 | |
| 61. | Divinum Illud Munus | On the Holy Spirit | 9 May 1897 | |
| 62. | Militantis Ecclesiae | On St. Peter Canisius | 1 August 1897 | |
| 63. | Augustissimae Virginis Mariae | Of the Most August Virgin Mary | On the Confraternity of the Holy Rosary | 12 September 1897 |
| 64. | Affari Vos | On the Manitoba School Question | 8 December 1897 | |
| 65. | Caritatis Studium | Of the studies of charity | On the Church in Scotland | 25 July 1898 |
| 66. | Spesse Volte | On the Suppression of Catholic Institutions | 5 August 1898 | |
| 67. | Quam Religiosa | On Civil Marriage Law | 16 August 1898 | |
| 68. | Diuturni Temporis | On the Rosary | 5 September 1898 | |
| 69. | Quum Diuturnum | On the Latin American Bishops' Plenary Council | 25 December 1898 | |
| 70. | Testem Benevolentiae Nostrae | Virtue, Nature and Grace, and Americanism | 22 January 1899 | |
| 71. | Annum Sacrum | A Holy Year | Consecration to the Sacred Heart | 25 May 1899 |
| 72. | Depuis Le Jour | "Since the Day " | On the Education of the Clergy | 8 September 1899 |
| 73. | Paternae | "Fathers " | On the Education of the Clergy | 18 September 1899 |
| 74. | Omnibus Compertum | On Unity Among the Greek | 21 July 1900 | |
| 75. | Tametsi Futura Prospicientibus | On Jesus Christ the Redeemer | 1 November 1900 | |
| 76. | Graves de Communi Re | On Christian Democracy | 18 January 1901 | |
| 77. | Gravissimas | The Gravest | On Religious Orders in Portugal | 16 May 1901 |
| 78. | Reputantiubus | On the Language Question in Bohemia | 20 August 1901 | |
| 79. | Urbanitatis Veteris | On the Foundation of a Seminary in Athens | 20 November 1901 | |
| 80. | In Amplissimo | On the Church in the United States | 15 April 1902 | |
| 81. | Quod Votis | On the Proposed Catholic University | 30 April 1902 | |
| 82. | Mirae Caritatis | Mirror of Charity | On the Holy Eucharist | 28 May 1902 |
| 83. | Quae Ad Nos | On the Church in Bohemia and Moravia | 22 November 1902 | |
| 84. | Fin Dal Principio | On the Education of the Clergy | 8 December 1902 | |
| 85. | Dum Multa | Marriage Legislation | 24 December 1902 |