Final answer:
The Egyptian and Persian civilizations are the two ancient civilizations that existed in the BCE timeline.
Step-by-step explanation:
The two ancient civilizations that existed in the BCE (Before Common Era) timeline are the Egyptian and Persian civilizations. These civilizations thrived long before the Common Era, with Egypt's history beginning around 3100 BCE, during the Early Dynastic Period of Egypt, and continuing through various phases including the Old, Middle, and New Kingdoms. The Persian civilization, often associated with the Achaemenid Empire founded by Cyrus the Great around 550 BCE, was also a significant and influential ancient civilization.