INNOCENT III. (LOTHARIO CONTI), by far the greatest pope of this name, was born at Anagni in 1161. After a course of much distinction at Paris, Bologna, and Rome, he was made cardinal; and eventually in 1198 was elected, at the unprecedentedly early age of thirty-seven, a successor of Pope Celestine III. His pontificate is justly regarded as the culminating point of the temporal as well as the spiritual supremacy of the Roman see; under the impulse of his ardent but disinterested zeal for the glory of the church, almost every state and kingdom was brought into subjection. In Italy, during the minority of Frederick II., who was a ward of Innocent's, the authority of the pope within his own states was fully consolidated, and his influence among the other states of Italy was confirmed and extended. In Germany he adjudicated with authority upon the rival claims of Otto the Guelph and Philip of Swabia; in France he compelled Philip Augustus to dismiss Agnes de Meranie, whom he had unlawfully married, and to take back Ingeburga. In Spain he exercised a similar authority over the king of Leon. The history of his conflict with and triumph over John of England displays in a stronger light the extent of his pretensions and the completeness of his supremacy. Even the king of Armenia, Leo, received his legates. And, as if in order that nothing might be wanting to the completeness of his authority throughout the then known world, the Latin conquest of Constantinople and the establishment of the Latin kingdom of Jerusalem put an end, at least during his pontificate, to the shadowy pretensions of the eastern rivals of his power, spiritual as well as temporal. His views of the absoluteness of the authority of the church within her own dominion were no less unbending than his notion of the universality of its extent. To him every offence against religion was a crime against society, and in his ideal Christian republic every heresy was a rebellion which it was the duty of the rulers to resist and repress. It was at his call, therefore, that the crusade against the Albigensians was organised and undertaken. As an ecclesiastical administrator Innocent holds a high place in his order. He was a vigorous guardian of public and private morality, a steady protector of the weak, zealous in the repression of simony and other abuses of the time. He prohibited the arbitrary multiplication of religious orders by private authority, but he lent all the force of his power and influence to the remarkable spiritual movement in which the two great orders, the Franciscan and the Dominican, had their origin. It was under him that the celebrated fourth Lateran Council was held in 1215. In the following year he was seized with his fatal illness, and died in July at Perugia at the early age of fifty-six. His works embrace sermons, a remarkable treatise on the Misery of the Condition of Man, and a large number of letters. The 'golden sequence' 'Veni, sancte Spiritus' has been attributed to him by some. It is from his letters and his decretals alone that the character of the age and the true significance of the church policy of this extraordinary man can be fully understood. However earnestly men may dissent from these views, no student of medieval history will refuse to accept Dean Milman's verdict on the career of Innocent III. that 'his high and blameless, and, in some respects, wise and gentle character, seems to approach more nearly than any one of the whole succession of Roman bishops to the ideal light of a supreme pontiff;' and that 'in him, if ever, may seem to be realised the churchman's highest conception of a vicar of Christ.'
See Milman's Latin Christianity, vol. v.; Jorry's Histoire du Pape Innocent III. (1853); and the works in German by F. Hurter (1834-42), Deutsch (1876), Schwemer (1882), and Brischar (1883).