Saint Irenaeus of Lyons is depicted in a stained glass window in the Basilica of Our Lady Immaculate in Guelph, Ontario. Pope Francis received a formal recommendation Jan. 20 to declare Saint Irenaeus of Lyon a Doctor of the Church, the Vatican announced. (Photo CNS/Les Croisiers)

VATICAN CITY (CNS) — Pope Francis has officially declared Saint Irenaeus of Lyon a Doctor of the Church.

In a decree issued by the Vatican on Jan. 21, the pope ordered that the 2nd-century theologian be given the title “doctor of unity” and said the life and teachings of Saint Irenaeus serve as a “spiritual bridge and theology between Eastern and Western Christians.

“May the doctrine of such a great master encourage more and more the journey of all the Lord’s disciples towards full communion,” the pope said.

During a meeting with Pope Francis on January 20, Cardinal Marcello Semeraro, prefect of the Congregation for the Causes of Saints, asked the pope “to accept the affirmative opinion” of the cardinals and bishops who are members of the congregation for conferring the title on Saint Irenaeus, who was known for his defense of orthodoxy amid the rise of Gnostic sects.

Saint Irenaeus is the second Doctor of the Church appointed by Pope Francis after Saint Gregory of Narek, who received the designation in 2015. He brings the total number of Doctors of the Church to 37.

Born in Smyrna, Asia Minor – now modern Turkey – Saint Irenaeus was known as a staunch defender of the faith.

Concerned with the rise of Gnostic sects within the early Christian church, he wrote “Adversus haereses” (“Against Heresies”), a refutation of Gnostic beliefs that emphasized personal spiritual knowledge rather than faith in Christian teachings and in ecclesiastical authority.

In October, the pope told members of the St. Irenaeus Orthodox-Catholic Joint Task Force that he intended to declare their namesake Doctor of the Church.

“Your patron, Saint Irenaeus of Lyons — whom I will soon declare a doctor of the Church with the title of “doctor unitatis” (“doctor of unity”) — came from the East, exercised his episcopal ministry in the West, and was a great spiritual and theological bridge between Christians of East and West,” he said.

During his meeting with Cardinal Semeraro, Pope Francis also signed decrees acknowledging how three candidates for sainthood – one man and two women – heroically lived out the Christian virtues. The three were:

— Italian Archbishop Francesco Saverio Toppi, former prelate of Pompeii, known for his devotion to Our Lady of the Most Holy Rosary. He was born in 1925 and died in 2007.

— Italian Sister Maria Teresa De Vincenti, founder of the Little Workers of the Sacred Heart. She was born in 1872 and died in 1936.

— Italian Sister Gabriella Borgarino, member of the Daughters of Charity. She was born in 1880 and died in 1949.