His thematic emphasis on freedom provoked his critics, who charged him with perverting the youth. Lacordaire was reputed to be the greatest pulpit orator of the nineteenth century. Lacordaire's preaching was not so much penitential as an exercise in apologetics. He demonstrated that one could be a French citizen and a Catholic. The lectures were a great success. Monseigneur de Quélen, the Archbishop of Paris, asked Lacordaire to preach a Lenten series in 1835 at the Cathedral of Notre-Dame in Paris, as part of the Notre-Dame Lectures specially aimed at the catechesis of Christian youth, which had been inaugurated at the behest of his friend Ozanam. Lacordaire's first lecture took place on 8 March 1835, and was met with wide acclaim. The social event of its day, 6,000 attended. Because of this immediate success, he was asked to preach again the following year. According to Thomas Bokenkotter, Lacordaire's Notre Dame Conferences, "...proved to be one of the most dramatic events of nineteenth century church history." Today the Lacordaire Notre-Dame Lectures, which mixed theology, philosophy and poetry, are still acclaimed as a sublime modern re-invigoration of traditional homiletics. Among those who attended his Lenten sermons in 1836 was Marie-Eugénie de Jésus de Milleret. The encounter with Lacordaire marked a turning point in her life and the beginning of a spiritual journey that would eventually lead her to found the Religious of the Assumption. In a letter written to Lacordaire years later, she recalled, "Your words gave me a faith which henceforth nothing could shake." But in 1836 after such considerable success, he was still the object of mounting attacks on his theological stance. Suddenly his mother died. Lacordaire, aware of the need to continue his theological studies, retreated to Rome to study with the Jesuits. There, he published his "Letter on the Holy See" in which he reaffirmed with vigor his ultramontane positions, insisting on the primacy of the Roman Pontiff, "the one and permanent trustee, supreme organ of the Gospel, and the sacred source of the universal communion." This text ran afoul of the Archbishop of Paris, Monseigneur Quélen, who was a sincere Gallican. In 1837, seeing the example of Guéranger's restoration of the Benedictines, Lacordaire decided to enter the Dominican Order despite the loss of certain personal freedoms that would entail, and to re-establish the Dominicans in France.