Pope Lucius II, during the whole of his pontificate, had to face the municipal commune at Rome, hostile towards the secular rule of the popes in the Eternal City. The republican faction elected Giordano Pierleoni, brother of the former Antipope Anacletus II, to the post of senator, and demanded that Lucius relinquish all temporal matters into his hands. The pope refused and led the small army against the seat of the commune on Capitol. He was defeated and seriously wounded in this attack, and died on 15 February 1145 in the church of S. Gregorio in clivo scauri. The cardinals present at Rome quickly assembled in the church of San Cesareo in Palatio and on the very same day unanimously elected to the papacy Bernardo da Pisa, pupil of St. Bernard of Clairvaux, who was abbot of the Cistercian monastery of S. Anastasio alle Tre Fontane near Rome and probably did not belong to he College of Cardinals. The elect took the name of Eugene III. Due to hostility of the Roman people, his consecration took place in the monastery of Farfa on 18 February 1145.
There were probably 40 cardinals in the Sacred College of Cardinals in February 1145. Based on the examination of the subscriptions of the papal bulls in 1145 and the available data about the external missions of the cardinals it is possible to establish that no more than 34 cardinals participated in the election:
^Bernardo's cardinalate is attested in some of the contemporary chronicles (cited by Bernhardi, p. 452 note 4); however, there are doubts concerning their factual accuracy due to lack of other documentary proofs of this affirmation, particularly the silence of Liber Pontificalis and the official papal documents. Bernhardi, pp. 451–452; Brixius, p. 41 no. 7; and Zenker, pp. 185–186 concluded that he was actually promoted to the cardinalate. Refutation by Horn, pp. 42–45.
^Reconstruction is based on Brixius, p. 22 note 6, and Horn, pp. 304–305, with the following correction: bishop Rodolfo of Orte (listed by Brixius) has been excluded because he was not a cardinal at that time (Zenker, pp. 52–53). Besides, the elect is not listed as cardinal, although Brixius indicates that he was.
^Kehr, vol. VI/1, p. XXVIII and vol. VI/2, p. XXI; Karol Maleczyński, Studia nad dokumentem polskim, Wrocław 1971, p. 61 note 49. He did not subscribe any papal bulls between 30 April 1144 and 21 December 1145 (Jaffé, pp. 7 and 20)
^Karol Maleczyński, Studia nad dokumentem polskim, Wrocław 1971, pp. 55–76; He did not subscribe any papal bulls between 19 February 1144 and 9 October 1145 (Jaffé, pp. 1, 7 and 20)