Short answers, pulled from the story.
The word religion did not exist in the ancient world and was forged in the 16th and 17th centuries by European scholars. This modern category was created to describe diverse spiritual practices encountered during the age of exploration. Before this linguistic invention, there was only the specific practice of a people, their gods, and their rituals without a unifying label.
Göbekli Tepe is the oldest potentially religious site yet discovered and features circles of massive T-shaped stone pillars decorated with abstract pictograms and carved animal reliefs. This site was built before the Neolithic Revolution around 9000 BCE. The abandonment of Göbekli Tepe coincides with the rise of agricultural societies.
The axial age occurred between 900 and 200 BCE and saw the spiritual foundations of humanity laid simultaneously and independently across Eurasia. During this era, monotheism emerged in Persia and Canaan, Platonism took root in Greece, and Buddhism and Jainism arose in India. Confucianism and Taoism also developed in China during this time.
The Pyramid Texts from ancient Egypt dating between 2400 and 2300 BCE stand as the oldest known religious texts in the world. These texts predate the earliest records of Indian religion known as the Vedas. Surviving early copies of religious texts include the Upanishads which date to the mid-first millennium BCE.
World religions of the present day established themselves throughout Eurasia during the Middle Ages through a complex web of conflict and conversion. The Christianization of the Western world and the spread of Islam throughout the Middle East, Central Asia, North Africa, and parts of Europe and India reshaped the geopolitical landscape. The Crusades began in 1095 and the Reconquista lasted from 718 to 1492.
Wars of religion broke out and culminated in the Thirty Years' War which ravaged Central Europe between 1618 and 1648. This conflict demonstrated the destructive power of religious division and followed the rapid spread of the Protestant Reformation under leaders such as Martin Luther between 1483 and 1546. The 18th century saw the beginning of secularization in Europe which gained momentum after the French Revolution broke out in 1789.