Christianity. Christianity is an Abrahamic religion that began as a Jewish sect in the mid-1st century. Originating in the Levant region of the Middle East, it quickly spread to Syria, Mesopotamia, Asia Minor and Egypt. It grew in size and influence over a few centuries, and by the end of the 4th century had become the official state church of the Roman Empire, replacing other forms of religion practiced under Roman rule. During the Middle Ages, most of the remainder of Europe was Christianized, and adherents were gained in the Middle East, North Africa, Ethiopia and parts of India. Following the Age of Discovery, Christianity spread to the Americas, Australasia, sub-Saharan Africa, and the rest of the world through missionary work and colonization. Christianity has played a prominent role in the shaping of Western civilization.
Islam. Islam (/ˈɪslɑːm/;[note 1] Arabic: الإسلام, al-ʾIslām IPA: [ælʔɪsˈlæːm] ( )[note 2]) is a monotheistic and Abrahamic religion articulated by the Qur'an, an Islamic holy book considered by its adherents to be the verbatim word of God (Allāh), and for the vast majority of adherents, also by the teachings and normative example (called the Sunnah and composed of hadith) of Muhammad (c. 570–8 June 632 CE), considered by most of them to be the last prophet of God.
An adherent of Islam is called a Muslim. Buddhism. Two major branches of Buddhism are generally recognized: Theravada ("The School of the Elders") and Mahayana ("The Great Vehicle").
Theravada has a widespread following in Sri Lanka and Southeast Asia (Cambodia, Laos, Thailand, Myanmar etc.). Mahayana is found throughout East Asia (China, Korea, Japan, Vietnam, Singapore, Taiwan etc.) and includes the traditions of Pure Land, Zen, Nichiren Buddhism, Tibetan Buddhism, Shingon, and Tiantai (Tendai). In some classifications, Vajrayana—practiced mainly in Tibet and Mongolia, and adjacent parts of China and Russia—is recognized as a third branch, while others classify it as a part of Mahayana. Platonism. Platonism (with a capital "P") is the philosophy of Plato or the name of other philosophical systems considered closely derived from it.
With a lower case "p", "platonism" refers to the philosophy that affirms the existence of abstract objects, which are asserted to "exist" in a "third realm distinct both from the sensible external world and from the internal world of consciousness, and is the opposite of nominalism (with a lower case "n"). Lower case "platonists" need not accept any of the doctrines of Plato. Philosophy Origin of the "Christian" Fish Symbol. Most symbols that people use have a story behind them and are used to make a statement.
Some of the most famous are the so-called Christian symbols such as the cross and the fish. Whilst they provide a useful mean of identification, all of these are carnal and nowadays used promiscuously by everybody, thus it is best for us to avoid using them.