The history of religion has been shaped by the events, periods, and politics of the world.
Some sources point to the Neanderthals as first hominids to perform burials of the dead about 100,000 years ago. Their grave contained the body of the deceased and various grave goods, signifying a belief in afterlife. Ancient burial sites have been discovered in Iraq, Israel, and Croatia. Paganism and ancestor worship were practiced at the time. With the development of agriculture during the Neolithic period about 11,000 years ago, populations were less nomadic and societies came into being. Eventually, states were created and religion was adapted to fit the state society.
It was not until the Late Bronze Age and Iron Age that people started accepting religions that were not polytheistic. Henotheism, or the worship of one god and belief in many gods, was developed. This was followed by the development of monotheistic religions which only believed in the existence of one God. Judaism was founded and eventually brought upon the birth of Christianity. These two religions along with Islam, which developed a few centuries later, make the Abrahamic religions, the largest religious grouping. Some sources also group Baha'i, which came centuries later, with Abrahamic religions.
Before Judaism came along, Hinduism, the world's oldest existing religion, was already being practiced on the Indian subcontinent. Zoroastrianism was eventually practiced in Persia (modern Iran). India and parts of East Asia were very involved in spirituality and this is reflected in the different types of religions that came from the area throughout the centuries. Far Eastern religions include Shinto and Taoism. Besides Hinduism, Indian religions are Buddhism, Jainism, and Sikhism. Besides Zoroastrianism, Iranic religions also include Baha'i.
The Middle Ages were very significant to the history of religion. Modern versions of religions were defined and established at this time: Christianity established itself in Europe; Buddhism spread to East Asia; Hinduism developed in the Indian subcontinent; Islam gained a following throughout the Middle East, North Africa, Central Asia, and some regions India and Europe. The Middle Ages were also a time of conflict and war (Religion & War). Islam, Christianity and Paganism all clashed with one another. Islam also clashed with Zoroastrianism, Hinduism, and Sikhism, while Christianity also clashed with Judaism, and Paganism also clashed with Buddhism and Taoism.
During the modern period of religious history, the effects of European colonization were felt with the spread of Christianity to parts of Africa, Australia, and the Americas from the 15th to 19th centuries. In the meantime many new religions, which blended elements of different religions, formed. Diasporic religions built on traditional religions of Africa, like Santeria, Candomble, and Rastafari, were products of the colonization and slave trade. In response to the Protestant Reformation, Unitarianism was formed in Europe. It established itself in the United States in the 1800s. This was also a time when the Mormon Church and the Jehovah's Witnesses were founded in the United States. These religions gained a following, along with heavy criticism. One tradition that is all too familiar with criticism is Atheism, which has roots in the Greek and Roman Classical Age and has managed to survive throughout the centuries.