Immortale Dei

Immortale Dei (1885)

• Full title: Immortale Dei: On the Christian Constitution of States
• Date: 1 November 1885
• Author: Pope Leo XIII

Core themes

• Reflects on the proper relationship between Church and state.
• Affirms that political authority comes from God and must be exercised according to the moral law.
• Recognizes that different forms of government can be legitimate, provided they respect:
  • Human dignity
  • The rights of the Church
  • The common good.
• Warns against secularism that excludes religion from public life and against state control over the Church.

Lasting impact

• Important text for understanding 19th‑century Catholic teaching on politics and society.
• Anticipates later reflections on religious freedom, the role of conscience, and pluralistic societies.
• Frequently cited in discussions of how Catholics should engage with modern political orders.