He was born Giacomo Savelli, of the rich and influential Roman family of the Savelli that had provided three popes, Benedict II, Gregory II and his great-uncle, Pope Honorius III.
When Martin IV died 28 March, 1285, at Perugia, Cardinal Savelli was unanimously elected pope on April 2 and took the name of Honorius IV. His election was one of the speediest in the history of the papacy. On May 20, he was consecrated bishop and crowned pope in the Basilica of St. Peter. Honorius was already advanced in age and so severely affected with the gout that he could neither stand nor walk. When saying Mass he was obliged to sit on a stool and at the elevation of the host his hands had to be raised by a mechanical contrivance.
Sicilian affairs required immediate attention. Previously, under Martin IV, the Sicilians had rejected the rule of Charles of Anjou, taking Pedro III of Aragon as their king without the consent and approval of the pope.
The massacre of 31 March 1282, known as the Sicilian Vespers, had precluded any reconciliation; Martin put Sicily and Pedro III under an interdict, deprived Pedro of the Kingdom of Aragon, and gave it to Charles of Valois, the younger of the sons of King Philip III of France whom he assisted in his attempts to recover Sicily by force of arms. The Sicilians not only repulsed the attacks of the combined Franch and Papal forces but also captured the Angevin heir, Charles of Salerno. On 6 January, 1285, Charles of Anjou died, leaving his captive son Charles of Salerno as his natural successor. Honorius, more peaceably inclined than Martin IV, did not renounce the Church's support of the House of Anjou, nor did he set aside the severe ecclesiastical punishments imposed upon Sicily.
On the other hand, he did not approve of the tyrannical government to which the Sicilians had been subject under Charles of Anjou. This is evident from his wise legislation as embodied in his constitution of 17 September, 1285 (Constitutio super ordinatione regni Siciliae) in which he stated that no government can prosper which is not founded on justice and peace, and passed forty-five ordinances intended chiefly to protect the people of Sicily against their king and his officials.
The death of Pedro III on November 11, 1285 changed the Sicilian situation in that his kingdoms were divided between his two sons Alfonso receiving the crown of Aragon and James succeeding as King of Sicily. Honorius IV acknowledged neither the one nor the other: on 11 April 1286, he solemnly excommunicated King James of Sicily and the bishops who had taken part in his coronation at Palermo on February 2. Neither the king nor the bishops concerned themselves about the excommunication. The king even sent a hostile fleet to the Roman coast and destroyed the city of Astura by fire.
Charles of Salerno, the Angevin pretender, who was still held captive by the Sicilians, finally grew tired of his long captivity and signed a contract on February 27, 1287, in which he renounced his claims to the Kingdom of Sicily in favour of James of Aragon and his heirs. Honorius, however, declared the contract invalid and forbade all similar agreements for the future.
While Honorius was inexorable in the stand he had taken towards Sicily, his relations towards Alfonso of Aragon became less hostile. Through the efforts of King Edward I of England, negotiations for peace were begun by Honorius and King Alfonso. The pope, however, did not live long enough to complete these negotiations, which finally resulted in a peaceful settlement of the Aragonese as well as the Sicilian question in 1302 under Boniface VIII.
Rome and the States of the Church enjoyed a period of tranquility during the pontificate of Honorius IV, the like of which they had not enjoyed for many years. He had the satisfaction of reducing the most powerful and obstinate enemy of papal authority, Count Guido of Montefeltro, who for many years had successfully resisted the papal troops. The authority of the pope was now recognized throughout the papal territory, which then comprised the Exarchate of Ravenna, the March of Ancona, the Duchy of Spoleto, the County of Bertinoro, the Mathildian lands, and the Pentapolis, viz. the cities of Rimini, Pesaro, Fano, Senigallia, and Ancona. Honorius was the first pope to employ the great family banking houses of central and northern Italy for the collection of papal dues.
The Romans were greatly elated at the election of Honorius IV, for he was a citizen of Rome and a brother of Pandulf, a senator of Rome. The continuous disturbances in Rome during the pontificate of Martin V had not allowed that pope to reside in Rome, but now the Romans cordially invited Honorius IV to make Rome his permanent residence. During the first few months of his pontificate he lived in the Vatican, but in the autumn of 1285 he removed to the magnificent palace which he had just erected on the Aventine.
In his relations with the empire, where no more danger was to be apprehended since the fall of the Hohenstaufen, he followed the via media taken by Gregory X. Rudolf of Habsburg sent Bishop Henry of Basel to Rome to request coronation. Honorius appointed the envoy archbishop of Mainz, fixed a date for the coronation, and sent Cardinal John of Tusculum to Germany to assist Rudolf's cause. But general opposition showed itself to the papal interference; a council at Würzburg (16-18 March, 1287) protested energetically, and Rudolf had to protect the legate from personal violence, so that both his plans and the pope's failed.
Honorius IV inherited plans for another crusade, but confined himself to collecting the tithes imposed by the Council of Lyons, arranging with the great banking-houses of Florence, Siena, and Pistoia to act as his agents.
The two largest religious orders received many new privileges from Honorius IV, documented in his Regesta. He often appointed them to special missions and to bishoprics, and gave them exclusive charge of the Inquisition.
He also approved the privileges of the Carmelites and the Augustinian hermits and permitted the former to exchange their striped habit for a white one. He was especially devoted to the order founded by William X of Aquitaine (d. 1156), and added numerous privileges to those which they had already received from Alexander IV and Urban IV. Besides turning over to them some deserted Benedictine monasteries, he presented them with the monastery of St. Paul at Albano, which he himself had founded and richly endowed when he was still cardinal.
Salimbene, the chronicler of Parma, asserted that Honorius was a foe to the religious orders. This may reflect the fact that he opposed the Apostolic Brethren, an order embracing evangelical poverty that had been started by Gerard Segarelli at Parma in 1260. On 11 March, 1286, he issued a bull condemning them as heretics.
At the University of Paris he advocated the establishment of chairs for Eastern languages in order to give an opportunity of studying these languages to those who intended to labour for the conversion of the Muslims and the reunion of the schismatic churches in the East.
He raised only one man to be cardinal, his cousin Giovanni Boccamazza (or Boccamiti), archbishop of Monreale, 22 December, 1285.
The tomb of Honorius IV is in the church of Santa Maria in Aracoeli, Rome.