Saint Denis (a westernization of the the Greek Dionysius), was one of seven bishops sent to Gaul by the Bishop of Rome during the reign of the Emperor Deccius. Their mission was to extend the spread of the Gospel in that mostly-pagan land.

While most of the bishops were sent to major settlements, St Denis was assigned to the small, remote pagan town of Lutetia — which later grew to become the city of Paris. He and his companions settled outside the town in a house given to him by a convert, where the few Christians could meet in secret.

Soon, through the holy bishop's grace-filled preaching and his many miracles, Christianity grew rapidly.

Soon a fierce persecution of Christians swept through Gaul, and many of the faithful were abused, tortured or put to death. Saint Denis, fearless of danger and heedless of his own old age, travelled among the Christians, visiting the prisoners and exhorting all to remain firm in their confession of Christ.

Soon he himself was arrested along with several companions, and was tortured without pity. When was publicly hung on a cross, he preached to the onlookers of the mystery of Christ's Passion.

Taken back to prison, he celebrated the holy Eucharist for the last time, enveloped in a heavenly light. He and a host of other Martyrs were then beheaded on a hill, now called Montmartre in their memory.

There is a tradition that at his beheading he rose up, took his own head in his hands, and walked for several miles to a place that later became the Basilica of St Denis in the town named after him.

Before the French Revolution, the Kings and Queens of France were buried in this church.