Here are a few more quotes to chew on, regarding the amalgamation of apostate Christianity and paganism, which is the Church of Rome.
"There is scarcely anything which strikes the mind of the careful student of ancient ecclesiastical history with greater surprise than the comparatively early period at which many of the corruption's of Christianity, which are embodied in the Romish system, took their rise, yet it is not to be supposed that when the first originators of many of these unscriptural notions and practices planted those germs of corruption, they anticipated or even imagined they would ever grow into such a vast and hideous system of superstition and error as is that of popery. "-- John Dowling, History of Romanism, 13th ed., i 1, sec. 1, p. 65 [Dowling was a Protestant clergyman and historian of the early nineteenth century].
"The Church made a sacred day of Sunday . . . largely because it was the weekly festival of the sun;-- for it was a definite Christian policy to take over the pagan festivals endeared to the people by tradition, and to give them a Christian significance." --Arthur Weigall, The Paganism in Our Christianity, 1928, p. 145 [Dr. A. E. Weigall (1880-1937) was a high-ranking British Egyptologist in the Egyptian Government].
"Cults of the sun, as we know from many sources, had attained great vogue during the second, third, and fourth centuries. Sun-worshipers indeed formed one of the big groups in that religious world in which Christianity was fighting for a place. Many of them became converts to Christianity . . . Worshipers in St. Peter's turned away from the altar and faced the door so that they could adore the rising sun."--Gordon J. Laing, Survivals of Roman Religion, p. 192. [Dr. Laing(1869-1945) was a Canadian-born university professor and later dean at the University of Chicago].
"The early Christians had at first adopted the Jewish seven-day week with its numbered week days, but by the close of the third century A.D. this began to give way to the planetary week; and in the fourth and fifth centuries the pagan designations became generally accepted in the western half of Christendom. The use of the planetary names by Christians attests the growing influence of astrological speculations introduced by converts from paganism . . . During these same centuries the spread of Oriental solar [sun] worships, especially that of Mithra [Persian sun worship], in the Roman world, had already led to the substitution by pagans of dies Solis for dies Saturni, as the first day of the planetary week. Thus gradually a pagan institution was engrafted on Christianity." --Hutton Webster, Rest Days, pp. 220-221. [Webster (1875-?), was an author, historian, and professor at the University of Nebraska].
Certain historians agree that it was the pagan sun-worshipers--and not Christians--who first gave the name 'Lord's day' to Sunday. "The first day of each week, Sunday, was consecrated to Mithra [the most widely known sun-god of the early Christian centuries] since times remote, as several authors affirm. Because the Sun was god, the Lord par excellence, Sunday came to be called the 'Lord's day,' as later was done by Christianity."--Agostinho de Almeida Paiva, 0 Mitraiomo, p. 3.
"The retention of the old pagan name, 'Dies Solis' [day of the Sun] or 'Sunday' for the weekly Christian festival, is, in great measure, owing to the union of pagan and Christian sentiment, with which the first day of the week was recommended by Constantine to his subjects, Pagan and Christian alike, as the venerable day of the sun' . . . It was his mode of harmonizing the discordant religions of the empire under one common institution." --Dean Stanley [Episcopalian leader], Lectures on the Eastern Church, Lecture 6, p. 184.
"Constantine labored at this time untiringly to unite the worshipers of the old [pagan] and the new [Christian] faith in one religion. All his laws and contrivances are aimed at promoting this amalgamation [combining] of religions. He would by all lawful and peaceable means melt together a purified heathen ism and a moderated [compromising] Christianity . . . Of all his blending and melting together of Christianity and heathenism none is more easy to see through than this making of his Sunday law. The Christians worshiped their Christ, the heathen their sun-god; according to the opinion of the Emperor, the objects for worship in both religions being the same [the worship of a divine person on a select day of the week]."--H. G. Heggtveit, Illustreret Kirkehistorie, 1895, p. 202. [Hallvard Heggtveit (1850-1924) was a Norwegian church historian and teacher].
It was the Roman Imperial plan on several occasions, to unite all religions of the Empire into one religion--sun-worship: "The Jewish, the Samaritan, even the Christian, were to be fused and recast into one great system, of which the sun was to be the central object of adoration."--Henry Hart Milman, The History of Christianity, bk. 2, chap. 8 (Vol. II, p. 175). [Dr. Milman (1791-1868) was an important historian of England and dean of St. Paul's Cathedral in London].
When Christianity conquered Rome the ecclesiastical structure of the pagan church, the title and vestments of the pontifex maximus, the worship of the Great Mother and a multitude of comforting divinities, the sense of supersensible presences everywhere, the joy or solemnity of old festivals, and the pageantry of immemorial ceremony, passed like maternal blood into the new religion, and captive Rome captured her conqueror. The reins and skill of government were handed down by a dying empire to a virile papacy; the lost power of the broken sword was rewon by the magic of the consoling word; the armies of the state were replaced by the missionaries of the Church moving in all directions along the Roman roads; and the revolted provinces, accepting Christianity, again acknowledged the sovereignty of Rome. Through the long struggles of the Age of Faith the authority of the ancient capital persisted and grew, until in the Renaissance the classic culture seemed to rise from the grave, and the immortal city became once more the center of summit of the world's life and wealth and art. When, in 1936, Rome celebrated the 2689th anniversary of her foundation, she could look back upon the most impressive continuity of government and civilization in the history of mankind. May she rise again.(CAESAR AND CHRIST, A history of Roman Civilization and of Christianity from their beginnings to A.D.325. By Will Durant-1944)
I will give you a little time to dicredit these, before I submit some more for your consideration.