**Saint John XXIII (1958-1963), the “Good Pope,” is traditionally associated with the opening of Vatican II and the encyclical *Pacem in Terris*. Less known is his mariology: deeply traditional, simple, personally felt, and always present in his major social encyclicals.**

Pope	Saint John XXIII (Angelo Roncalli, 1958-1963)
Key Encyclicals	Mater et Magistra (May 15, 1961) \| Pacem in Terris (April 11, 1963) \| Aeterna Dei (1961)
Theme	Mary, Mother of the Church and of Peace, Mary simple and close to us

**Mater et Magistra (May 15, 1961), Marian Conclusion**

The social encyclical *Mater et Magistra* on the development of social relations concludes with an invocation to Mary, a tradition carried forward by all John XXIII’s successors:

> *”Beatiissima Virgo Maria, Mater Dei et nostra… spes afflictorum, salus morientium, levitatio cadentium, auxilium Christianorum, periculis mortis incidentium praesentissimum patrocinium, omnes tuet, omnibus auxilium implet.”*
>
> The Most Holy Virgin Mary, Mother of God and ours… hope of the afflicted, health of the dying, lifting up of the fallen, aid of Christians, present-day protection for those in peril by death, protect all, grant help to all.

**Pacem in Terris (April 11, 1963), The Peace Encyclical**

*Pacem in Terris*, published following the Cuban Missile Crisis (October 1962) and addressed for the first time to “all men of good will” (not just Catholics), also concludes with an invocation to Mary as Queen of Peace:

> *”Implorent Dominum, ut a Beatissima Virgine Maria, Pacis Regina ac Mater dulcissima, illud divinum donum, quod gentium seipsas composuit, fructum pacis caelestis generosissimam largire meretur…”*
>
> Let us implore the Lord to grant, through the Most Holy Virgin Mary, Queen of Peace and Mother most kind, that all peoples receive in abundance the divine gift by which they are reconciled, the fruit of heavenly peace…

**Aeterna Dei Sapientia (November 11, 1961), Encyclical on Saint Leo the Great**

John XXIII published this encyclical to mark the 1500th anniversary of the death of Saint Leo I (461). The text offers a dense account of Leo’s mariology: the Theotokos, virginity in childbirth, and the Incarnation of Mary. John XXIII uses the occasion to reassert the traditional patristic understanding of divine motherhood as a foundation for ecumenical unity between Rome and the Eastern Christian Church.

**Opening Address of Vatican II (October 11, 1962), Feast of the Maternity of Mary**

John XXIII opened the Second Vatican Council solemnly on October 11, 1962, which was then the feast day of the Maternity of Mary (later moved to January 1). This date was not chosen by chance: the Council emerged under the explicit patronage of Mary Theotokos. In his *Gaudet Mater Ecclesia* address, the Pope recalled that the Council of Ephesus (431), which defined the Theotokos, also paved the way for ecumenical unity.

## Meaning of John XXIII’s Mariology

The Pope Good’s mariology is that of the “simple Christian,” lacking major theoretical innovations but characterized by profound filial devotion. John XXIII conveyed traditional mariology through modern lenses in his social encyclicals, demonstrating that Mary is not alien to social issues and world peace. He laid the groundwork for Chapter VIII of *Lumen Gentium*.

## Additional Reading

– [Mariology](/mariologia/)
– [Chapter VIII of Lumen Gentium](/lumen-gentium/)
– [Marialis Cultus](/marialis-cultus/)
– [Post-Graduate Mariology Program](/pós-graduação-mariologia/)

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