Pius IX issued a Syllabus of Errors in 1864. The Syllabus proclaimed that it was an error to believe that human reason contradicted Christian faith, or to hold that Protestantism was merely another form of Christianity, or to claim that the Catholic religion should not be the sole religion of the state, to the exclusion of all other forms of worship. Article 80 proclaimed that it was an error to believe that ‘the Roman Pontiff can and ought to reconcile himself to, and agree with, progress, liberalism, and civilization as lately introduced’.
