Bl. John Duns Scotus (1266-1308)
Born a wealthy farmer, John was a Franciscan priest who lectured at Oxford and Cambridge for four years, and then traveled to Paris to teach and complete his doctorate. He is the founder of a school of scholastic thought called Scotism. His defense of the Immaculate Conception of Mary was so convincing that Pope Pius IX solemnly defined the dogma in 1854 largely due to his work.

Reflections from the Saints

The man who burns with the fire of divine love is a son of the Immaculate Heart of Mary, and wherever he goes, he enkindles that flame; he desires and works with all his strength to inflame all men with the fire of God's love. Nothing deters him: he rejoices in poverty; he labours strenuously; he welcomes hardships; he laughs off false accusations; he rejoices in anguish. He thinks only of how he might follow Jesus Christ and imitate him by his prayers, his labours, his sufferings, and by caring always and only for the glory of God and the salvation of souls.
– St. Anthony Mary Claret