The Feast of Saint Anselm is celebrated by Holy Mother Church on April 21st each year. This holy Successor of the Apostles and Doctor of the Church was a crusader against lay investiture, fiercely loyal to Rome and to his vocation as a priest who loved his flocks. 
They rewarded him by fiercely standing behind him against temporal kings. He was a Frenchman who conquered the Brits with love. He was the father of Scholastic Theology. He was the holy doctor from Piedmont whose writings and teachings became an important barometer for another Doctor of the Church - the angelic doctor. He was the uncompromising Archbishop of Canterbury in the middle ages who lived 76 years. He was
Saint Anselm.
St. Anselm was born in 1033 in the village of Aosta, Italy near Piedmont. When as a boy of fifteen he was forbidden to enter religion after the death of his good Christian mother, for a time he lost the fervor she had imparted to him. He left home and went to study in various schools in France; at length his vocation revived, despite his father's protests. To fulfill his vocation he was forced to flee to France where he entered the Benedictine monastery at Bec in Normandy, France at the age of 23 and became a Benedictine monk there studying under the renowned Abbot Lanfranc.
There he was also appointed abbot in 1078 and became known far and wide as a dynamic preacher. His prowess as a holy man reached across the channel to Britain where the English King William Rufus (William II) requested he become his highness' personal confessor. In 1092 the English clergy overwhelmingly beseeched him to become Archbishop of Canterbury which had been vacant for three years. While Anselm consented to it, he refused to compromise the Church's position with the state and the English king who, for worldly reasons, refused to acknowledge Anselm. Yet, Anselm was consecrated in December, 1093. Then began the strife which characterized Saint Anselm’s episcopate. The king, when restored to health, lapsed into his former sins, continued to plunder the Church lands, scorned the archbishop’s rebukes, and forbade him to go to Rome for the pallium.
Finally the king sent envoys to Rome for the pallium; a legate returned with them to England, bearing it. The Archbishop received the pallium not from the king’s hand, as William would have required, but from that of the papal legate. For Saint Anselm’s defense of the Pope’s supremacy in a Council at Rockingham, called in March of 1095, the worldly prelates did not scruple to call him a traitor. The Saint rose, and with calm dignity exclaimed, “If any man pretends that I violate my faith to my king because I will not reject the authority of the Holy See of Rome, let him stand, and in the name of God I will answer him as I ought.” No one took up the challenge; and to the disappointment of the king, the barons sided with the Saint, for they respected his courage and saw that his cause was their own. During a time he spent in Rome and France, canons were passed in Rome against the practice of lay investiture, and a decree of excommunication was issued against offenders.
To further aggravate the situation, William II demanded excessive payments from Anselm for the diocese which the latter refused to pay. Those who were not loyal to Rome backed the king against Anselm, but when the bishop made an impassioned plea to the people, "If any man pretends that I violate my faith to my king because I will not reject the authority of the Holy See of Rome, let him stand forth, and in the name of God I will answer him as I ought." The common people understood he was one of them and they rallied behind Anselm who fled England to Rome. There Pope Urban I backed Anselm and refused William's demands for fees or threats to confiscate diocesan property. The king realized he had met his match and the "vox populi" sounded solidly behind Anselm against the king. William wilted and died in 1100.
With the obstacle gone, Anselm returned triumphantly to England but ran into almost the same problems with William's successor King Henry II over lay investiture. Anselm returned to Rome where Urban's successor Pope Paschal II strongly supported the archbishop. Henry realized it was a no-win situation and recanted allowing Anselm to return and invest bishops and abbots himself instead of the king.
In 1102 at a synod in Westminster, Anselm was one of the first to vigorously denounce slave trade in Africa. In 1108, Henry made Anselm a regent and a year later Anselm passed on to his Heavenly reward when he breathed his last on April 21, 1109 at the age of seventy six.
Though he had been embroiled in many disputes with imperial parties during his bishopric, he wrote many tomes on theology and established a powerful influence on the people of his time. In the midst of his harassing cares, Saint Anselm found time for writings which have made him celebrated as the originator of scholastic theology, while in metaphysics and in science he had few equals. He is yet more famous for his devotion to our Blessed Mother, whose Feast of the Immaculate Conception he was the first to establish in the West. coming to be known as the "Father of Scholasticism." He was studied in depth by such luminaries as Saint Thomas Aquinas. In 1720 Pope Clement XI declared Anselm a "Doctor of the Church."
Note: [editor's bold, brackets and italicized for emphasis] Some of the sources taken from: Little Pictorial Lives of the Saints, a compilation based on Butler’s Lives of the Saints and other sources by John Gilmary Shea (Benziger Brothers: New York, 1894).