Past popes knew well that Freemasonry is Satan's chosen instrument for attacking the Catholic Church. To this day it remains the most condemned belief system in the Church's history.
Pope Leo XIII wrote an encyclical on Freemasonry in 1890 titled Dall'Alto Dell'Apostolico Seggio condemning masonic sects.
They are already judged; their ends, their means, their doctrines, and their action, are all known with indisputable certainty. Possessed by the spirit of Satan, whose instrument they are, they burn like him with a deadly and implacable hatred of Jesus Christ and of His work; and they endeavor by every means to overthrow and fetter it.
The concerned pontiff spoke of previous papal condemnations of this secret society, which cloaks itself in charitable garb.
Many times have We sounded the alarm, to give warning of the danger; but We do not therefore think that We have done enough. In face of the continued and fiercer assaults that are made, We hear the voice of duty calling upon Us more powerfully than before to speak to you again.
In his encyclical, the venerable Holy Father touches on some of the perverted goals of this seemingly altruistic society:
The masons laid out even more insidious plans to directly attack the Church in their document Alta Vendita. It's been called a masonic blueprint for destroying the Catholic Church by plotting to capture the papacy. Their plans fell into the hands of Pope Gregory XVI and were subsequently published under the authority of both Pope Pius IX and Pope Leo XIII.
The manifesto declares, "Our final end is that of Voltaire and of the French Revolution, the destruction forever of Catholicism and even of the Christian idea, which, if left standing on the ruins of Rome, would be the resuscitation of Christianity later on."
The document calls for corrupting the young clergy and religious with Feemasonry's secular humanist doctrines. This clergy would then go on to make revolutionary changes in the Church and select ill-formed leaders who would perpetuate these worldly errors.
Modern Freemasonry is thought to have originated in the Grand Lodge of London in 1717. Pope Clement XII in 1738 was the first Roman Pontiff to condemn Freemasonry with his papal bull, In Eminenti. Subsequent popes did likewise, namely, Benedict XIV, Pius VI, Leo XII, Pius VII, Pius VIII, Gregory XVI, Pius IX and Leo XIII.
The most recent statement against Freemasonry came from then-Cdl. Joseph Ratzinger as prefect of the Congregation for the Doctrine of the Faith. Following the promulgation of the current Code of Canon Law, Cdl. Ratzinger in 1983 affirmed that it was still a mortal sin for Catholics to become masons.
"The faithful who enroll in Masonic associations are in a state of grave sin and may not receive Holy Communion," he declared.
Pope Leo XIII in his encyclical Providentissimus Deus, describes the rationalists of the Enlightenment, like Voltaire, as spawn of Martin Luther's Protestant Revolt. Describing the enemy as those who espouse private judgment of Scripture, Leo XIII calls Catholics to battle "rationalists, true children and inheritors of the older heretics, who, trusting in their turn to their own way of thinking, have rejected even the scraps and remnants of Christian belief. ... They deny that there is any such thing as revelation or inspiration or Holy Scripture at all."
Pope Pius XII gives freemasons credit for begetting rationalists, communists and secular humanists. In his 1958 address to the Seventh Week Pastoral Adaptation Conference in Italy, Pius XII related, "[T]he roots of modern apostasy lay in scientific atheism, dialectical materialism, rationalism, illuminism, laicism and Freemasonry — which is the mother of them all."
The attacks on the Church by Communism alone are myriad. Dr. Alice von Hildebrand told Church Militant how one Communist, Bella Dodd, helped over a thousand Communist sympathizers become ordained priests. Their mission was to subvert the Church from within.
One such masonic French priest, who subsequently had a change of heart, revealed his marching orders stipulating how he was to adversely influence the Church. The plan was to encourage fellow Catholics to do the following:
Pope Leo XIII urged Catholics to ardently resist the multifaceted attacks of Freemasonry. The saintly Pope warned, "To shrink from seeing the gravity of this would be a fatal error." He admonished Catholics to fight the evil of this cult with all their might.
No means must be neglected that are in your power. All the resources of speech, every expedient in action, all the immense treasures of help and grace which the Church places in your hands, must be made use of, for the formation of a Clergy learned and full of the spirit of Jesus Christ, for the Christian education of youth, for the extirpation of evil doctrines, for the defence of Catholic truths, and for the maintenance of the Christian character and spirit of family life.