To more fully understand the Big Bang theory and the evidence on which it was based, an overview of its prior development over many centuries is needed. Today's ideas regarding the Big Bang theory can be considered to have originated in modern European science. However, before these ideas were developed, most explanations regarding the origins of the universe were based on religious themes and concepts, the main tradition of which was Christianity. These stories of Christian origin explain the appearance of the universe as the work of an omnipotent and omnipresent God. It is within this tradition that one of the first scientific attempts to understand the origins of our universe occurred. In the third century AD many Christian theologians were working to date the exact moment the universe began. Their research was based on the generations recorded in the Old Testament of the Bible, the Bible being an ultimately authoritative source according to their religion. These theologians estimated that the universe was more than 4,000 years old. Related to this early Christian cosmology was the work of Ptolemy of Alexandria, a Roman-Egyptian astronomer and mathematician. Ptolemy is known for rejecting early Greek models of the universe, which were generally accepted. Ptolemy argued that the earth was at the center of the universe, as opposed to the sun. This was disputed by Christian theologians, who argued that the Earth was too imperfect and full of sin. Despite this, most people accepted Ptolemy's model, in which the sun and planets revolved around the earth. Not only did it explain the movements of the solar system, but it further accommodated the idea that if the earth... in the center of the card... the universe was created and the possibility that time itself had come into being at the same time as where space, matter and energy were born. Another hole in the Big Bang cosmology is the one that appeared exactly 13 billion years ago and began creating matter and energy. This matter and energy became interchangeable in space, which was the size of an atom and was unimaginably hot. This exchange of energy and matter began to cool at an immense rate, while simultaneously beginning to expand. At this moment, estimated at a billionth of a billionth of a second, the universe is inflating at an extreme rate. Thus the fundamental forms of matter (dark and atomic) were created along with gravity, electromagnetism and nuclear forces. 20 minutes after the birth of energy and matter, their stability increased, with the appearance of protons and neutrons merging together.