Julius Firmicus Maternus was one of the fathers of horoscopic Astrology. He explained in detail in the 4th century A.D. the Hellenistic Horoscopic System introduced by Claudious Ptolemy, Vetious Valens and other Greek Astronomers of the 1st century A.D.
This book contains all sides and meanings of the Zodiac Signs, the planets, the system of the 12 houses and the aspects of the planets. Because of the abstract nature of the "Tetravivlos" of Claudious Ptolemy, "Mathseseos Libri" by Maternus is the full explanation of that theory which is also applied in our era.