Even today, religion and science continue to have antagonistic ideas. From the four river valley civilizations and early religions and philosophies, to Greek and Roman philosophies, Renaissance science, and the modern era, science and religion have a long history of conflict. In the beginning, religion was a driving force used to understand the world instead of science. Although around 5000 BC ancient civilizations used agriculture and were no longer nomadic peoples, faith and beliefs, including Animism, explained life and death. It was the idea that all of nature was alive. More complex belief systems such as Confucianism and Taoism developed later, around 551-479 BC, which also made primary contributions to the understanding of life and rebirth. These systems have come closer to using science than their predecessors, just as religions such as Judaism and even more so Christianity have come closer to using science as their primary understanding of the world. As time passes, science and religion slowly become in conflict as science began to explain concepts such as life, death, and creation that religion was accustomed to.