The Ancient Epoch is a period of time in Earth's history that began about 4.6 billion years ago and ended about 3.8 million years ago. It is divided into three main eras: the EOCENE (56 million to 33.9 million years ago), the AGE (33.9 million to 23 million years ago), and the Ice AGE (2.6 million to 11, 700 years ago). The EOCENE was characterized by warm temperatures and high sea levels, while the AGE saw the emergence of the first primates and the Ice AGE was marked by the formation of glaciers and ice sheets.