Pope Damasus II (died 9 August 1048), born Poppo de' Curagnoni, was Pope from 17 July 1048 to his death on 9 August that same year.
 He was the second of the German pontiffs nominated by Emperor Henry III.
 A native of Bavaria, he was the third German to become Pope and had one of the shortest papal reigns.
Pope Eugene III (Latin: "Eugenius III" ; c. 1080 – 8 July 1153), born Bernardo da Pisa, was Pope from 15 February 1145 to his death in 1153.
 He was the first Cistercian to become Pope.
 In response to the fall of Edessa to the Muslims in 1144, Eugene proclaimed the Second Crusade.
 The crusade failed to recapture Edessa, which was the first of many failures by the Christians in the crusades to recapture lands won in the First Crusade.
Matilda of Tuscany (Italian: "Matilde di Canossa", Latin: "Matilda", "Mathilda"; 1046 – 24 July 1115) was a powerful feudal ruler in northern Italy and the chief Italian supporter of Pope Gregory VII during the Investiture Controversy; in addition, she was one of the few medieval women to be remembered for her military accomplishments, thanks to which she was able to dominate all the territories north of the Church States.
Pope Adrian VI (Latin: "Hadrianus VI" ), born Adriaan Florensz (Boeyens) (2 March 1459 ‒ 14 September 1523), was head of the Catholic Church from 9 January 1522 until his death on 14 September 1523.
 The only Dutchman to become pope, he was the last non-Italian pope until John Paul II, 456 years later.
Beatrice of Bar (also "Beatrix") (c. 102018 April 1076) was a stateswoman and marchioness of Tuscany by marriage to Boniface III of Tuscany, and Regent of Tuscany from 1052 until her death during the minority of and in co-regency with her daughter Matilda.
 She was the daughter of Frederick II, Duke of Upper Lorraine, count of Bar, and Matilda of Swabia.
 She was married first to Boniface III of Tuscany and later to Godfrey of Lotharingia.
Friedrich Wetter (born 20 February 1928) is a German cardinal of the Catholic Church, the Archbishop Emeritus of Munich and Freising, Germany.
 His resignation as Metropolitan Archbishop of Munich and Freising was accepted on 2 February 2007 by Pope Benedict XVI, who was Cardinal Wetter's immediate predecessor in that post before going on to become Pope John Paul II's Prefect for the Congregation of the Doctrine of the Faith and then Pope.
The papal election of 1154 followed the death of Pope Anastasius IV and resulted in the election of Pope Adrian IV, the only Englishman to become pope.
Pope Sergius I (  650 8 September 701) was Pope from December 15, 687 to his death in 701.
 He was elected at a time when two rivals, the Archdeacon Paschal and the Archpriest Theodore, were locked in dispute about which of them should become pope.
Praedecessores nostros was a papal encyclical written by Pope Pius IX on March 25, 1847 to address the crisis of the Great Irish Famine that occurred approximately between 1845 and 1850.
 This event is known by many as the 19th century’s greatest natural disaster.
 Pope Pius IX was born Giovanni Maria Mastai-Ferretti on May 13, 1792 in Senigallia, Italy.
 He studied at the College of Volterra in Tuscany and was ordained as a priest in 1819.
 Throughout the span of his life, Pope Pius IX served as the director of the Roman hospice of San Michele, Bishop of Imola, and Archbishop of Spoleto.
 He was made a Cardinal (Catholicism) in 1840 and elected Pope in 1846.
 Several important events that occurred during the papacy of Pope Pius IX are the unification of Italy, the First Vatican Council, the defining of the dogma of the Immaculate Conception, and 38 papal encyclicals.
 "Praedecessores nostros" is one of the more significant papal decrees of the time because it addresses one of the most well known events in history.
 The Great Irish Famine was caused by the mysterious fungus, Phytophthora infestans.
 The fact that the potato was the main food of over half the population of Ireland caused approximately one million people to die as a consequence.
Gregory VII (Latin: "Gregorius VII" ; 1015 – 25 May 1085 AD), born Hildebrand of Sovana (Italian: "Ildebrando da Soana" ), was Pope from 22 April 1073 to his death in 1085.

Question: When did the Pope who was supported by Matilda of Tuscany become Pope?
Answer: 22 April 1073