The essential features of Freemasonry are called landmarks. No Masonic authority has the power to establish their number, but they are reputably from 15 to 60. The landmarks define the methods of recognition; the three-degree system of Blue Lodges; the right of every Mason to visit every regular lodge in the world, the belief in God (GAOTU) and in the immortality of the soul; the volume of sacred law (usually the Bible); the equality of all Masons in the lodge; the necessity of secrecy; and the symbolic method of teaching. The organization of the three-degree Masonic system as we know it today was completed by 1725. The five indispensable officers of a master mason's lodge are the Worshipful Master, Senior and Junior warden, the Secretary and the Orator. With the Director of Ceremonies and the Expert the Lodge becomes "just and perfect", that is regular. The ritual of the lodge is known as "work." Freemasonry teaches through symbols that reunite gnostic, deistic, or Christian elements. For example, the Masonic symbol "G" can stand for either God or geometry. A Masonic lodge will initiate a Christian, Jew, Muslim, Buddhist, Hindu, any adherent of any other religion and also any believer in God as a Supreme Being. Although Anglo-American tradition places a Holy Bible on its altar, an initiate may elect to swear his oaths on the Koran or the Vedas, or any scripture of his choice. Anderson's Constitution the first systematic rules of the Order states that a Mason, "if he rightly understand the Art, he will never be a stupid Atheist or an irreligious Libertine." Thus lodges will initiate an agnostic or freethinker but not an atheist. When the Grand Orient of France eliminated (Sept. 13, 1877) the requirements of belief in God and in the immortality of the soul, the United Grand Lodge of England and the majority of Grand Lodges immediately severed fraternal relations. This schism in worldwide Freemasonry has not been healed. Typically the Masonic lodges in Latin countries have appealed to freethinkers while those in England, northern Europe, and America draw their membership largely from Protestant churches. Portuguese freemasonry is enshrined in the first tradition and the Holly Book becomes a representation of God's teachings and not the dogma of God. Only atheists are non-qualified to be members of Portuguese freemasonry.