Nicolaus Copernicus’s book On the Revolutions of the Heavenly Spheres is added to the Index of Forbidden Books 73 years after it was first published.

The Index of Forbidden Books (Index Librorum Prohibitorum) was a list of publications deemed heretical, blasphemous, or morally corrupt by the Catholic Church. First published in 1559 under Pope Paul IV, it aimed to prevent the spread of ideas that contradicted Church doctrine, particularly those associated with Protestantism, scientific discoveries, and philosophical skepticism. The Index banned works by figures such as Galileo Galilei, Voltaire, and Jean-Jacques Rousseau, among others. While it was revised and republished multiple times, its influence gradually waned with the rise of secularism and intellectual freedom. In 1966, Pope Paul VI officially abolished the Index, acknowledging its obsolescence in a world of evolving academic and theological discourse. Despite its suppression, the Index remains a historical symbol of censorship and the struggle between religious authority and intellectual progress.