[321:5] He did insist, however, upon his dominion over Rome and over the Pope as his vassal. Pope Stephen IV. at once caused the Romans to swear fealty to the Emperor and ordained that the consecration of the Pope must take place in the presence of the imperial ambassadors. His son Lothair was crowned Emperor in Rome and repeatedly repaired thither to protect the Holy See. Another son, Louis, was also anointed king by Pope Sergius in Rome. This act strengthened the papal claim to control elections to secular power. In 871 Louis II. acknowledged his divine right to imperial rule to be derived from papal sanction. Another step was taken when the council of Aix-la-Chapelle deposed Emperor Lothair (842). CHAPTER XV THE PSEUDO-ISIDORIAN DECRETALS AND THE PAPAL CONSTITUTION OUTLINE: I.--What were the Pseudo-Isidorian Decretals? II.--Condition of Europe when the Decretals appeared. III.--Purpose of the forgery. IV.--Character and composition. V.--Time, place, and personality, of authorship. VI.--Significance and results. VII.--Nicholas I. and papal supremacy. VIII.--Decline of spirituality in the Church. IX.--Sources. The Pseudo-Isidorian Decretals[326:1] were a curious collection of documents, both genuine and forged, which appeared in western Europe about the middle of the ninth century under the name of Isidore Mercator, to give the Church a definite, written constitution. They were a stupendous forgery--the most audacious and pious fraud ever perpetrated in the history of the Church--worked out with admirable skill and consummate ingeniousness. Forgery was a common thing in those days, and it was generally believed that all things which upheld the doctrines and prerogatives of the Church of God were allowable.[326:2]