On Sept. 9, the Catholic Church celebrates St. Peter Claver, a Jesuit missionary who spent his life in the service of African slaves brought against their will to South America during the 17th century.

Peter Claver was born into a farming family in the Spanish region of Catalonia during 1581. He studied at the University of Barcelona as a young man, and joined the Jesuits as a novice at the age of 20.

While studying philosophy in Tarragona, Peter developed a friendship with an older Jesuit lay brother, Alphonsus Rodriguez. Although Alphonsus spent his days doing menial work as a door-keeper, he had immense insight into spiritual matters and encouraged Peter to become a missionary in the Spanish colonies. Pope Leo XIII would later canonize both men on the same day, almost two centuries later.

In 1610, Peter Claver – now a priest – arrived in Cartagena, a port city in present-day Colombia. Despite Pope Paul III’s repeated condemnations of slavery during the previous century, European colonists continued importing African slaves, often sold by their own rulers, to work on plantations and in mines. Those who survived the ship journey could expect to be worked to death by their masters.

Peter was determined to sacrifice his own freedom to bring material aid and eternal salvation to the African slaves, in keeping with his vow to become “the slave of the blacks forever.” The young priest made and kept this resolution despite his own health problems (aggravated by Cartagena’s tropical climate) and the language barrier between himself and the population he served.

Many Spanish Royal officials in Cartagena appreciated Claver’s work, and made contributions toward the slaves’ relief and religious education. The slave traders, on the other hand, found the priest and his interpreters to be a nuisance. Meanwhile, some Spanish expatriates who sought out the priest because of his holy reputation, refused to enter the same church or confessional as the black slaves.

In order to minister to speakers of a foreign language, Claver often employed pictorial representations of Catholic truths. He also communicated by means of generosity and expressions of love, giving food and drink to the ailing workers and visiting them during bouts of sickness that often proved fatal.

“We must speak to them with our hands,” he reasoned, “before we try to speak to them with our lips.”

In keeping with his vow of “slavery,” Peter survived on minimal amounts of food and sleep. His life of humility and penance led to miraculous occurrences – as when he healed the sick with the touch of his cloak, or appeared surrounded by a supernatural light during his hospital visits.

St. Peter Claver’s work came to an end with his death on September 8, 1654. He had baptized and taught the faith to more than 300,000 slaves during his four decades in Cartagena.

During the Vatican’s Synod for Africa in 2009, Cartagena’s Archbishop Jorge Enrique Jiménez Carvajal lamented the fact that his city had been the center of an “awful commerce.”

But he spoke with gratitude for the fact that the same city had become the home of such a “great witness to sanctity,” the “apostle of the slaves, whose body rests in our cathedral, who lived to protect them and lead them towards the faith” in which they could experience God’s love.