Ineffabilis Deus

bull by Pope Pius IX

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Last updated

June 29, 2026

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The Ineffabilis Deus is a papal bull issued by Pope Pius IX on December 8, 1854. This bull officially declared the Roman Catholic dogma of the Immaculate Conception.12

The doctrine of the Immaculate Conception states that Mary, the mother of Jesus, was preserved from original sin from the very first moment of her conception. This means she was uniquely favored by God's grace and free from sin's effects.13

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Immaculate Conception
…solemnly declared in the bull Ineffabilis Deus (“Ineffable God”) that the doctrine was revealed by God and hence was to be firmly believed as such by all Catholics.
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…solemnly declared in the bull Ineffabilis Deus (“Ineffable God”) that the doctrine was revealed by God and hence was to be firmly believed as such by all Catholics.
Read More