The origins of much of the astrology that would later develop in Asia, Europe and the Middle East are found among the ancient Babylonians and their system of celestial omens that began to be compiled around the middle of the 2nd millennium BCE. This system later spread either directly or indirectly through the Babylonians to other areas such as China and Greece where it merged with preexisting indigenous forms of astrology. It came to Greece initially as early as the middle of the 4th century BCE, and then around the late 2nd or early 1st century BCE after the Alexandrian conquests this Babylonian astrology was mixed with the Egyptian tradition of Decanic astrology to create horoscopic astrology. This system is labeled as "horoscopic astrology" because, unlike the previous traditions, it employed the use of the ascendant, otherwise known as the "horoskopos" ("hour marker") in Greek, and the twelve celestial houses which are derived from it. The focus on the natal chart of the individual, as derived from the position of the planets and stars at the time of birth, represents the most significant contribution and shift of emphasis that was made during the Hellenistic tradition of astrology. This new form of astrology quickly spread across the ancient world into Europe, and the Middle East.