History of the star: M42 is Nebula marking the sword-sheath or sword-scabbard of Orion, with the celebrated Trapezium in its midst. Known as Ensis to astrologers, this nebula's correct name is M42; The Great Orion Nebula, the name known to astronomers.

[Star Names, Their Lore and Meaning, Richard Hinchley Allen, 1889]

The astrological influences of the constellation: It is said to give a strong and dignified nature, self-confidence, inconstancy, arrogance, violence, impiety, and prosperity in trade and particularly in voyages or abroad, but danger of treachery and poison. It was thought by the Romans to be very harmful to cattle and productive of storms. By the Kabalists it is associated with the Hebrew letter Aleph and the 1^st Tarot Trump "The Juggler". (The Magician). (Robson*).  

The astrological influences of the constellation given by Manilius: 

Near neighbor to the Twins (Gemini), Orion may be seen stretching his arms over a vast expanse of sky and rising to the stars with no less huge a stride. A single light marks each of his shining shoulders, and three aslant trace the downward line of his sword ; but three mark Orion's head, which is imbedded in high heaven with his countenance remote." It is Orion who leads the constellations as they speed over the full circuit of heaven. [Astronomica, Manilius, 1st century AD. p.35.]

Orion will fashion alert minds and agile bodies, souls prompt to respond to duty's call, and hearts which press on with unflagging energy in spite of every trial. A son of Orion's will be worth a multitude and will seem to dwell in every quarter of the city; flying from door to door with the one word of morning greeting, he will enjoy the friendship of all. [Astronomica, Manilius, 1st century AD. p.305.]

References

*(Fixed Stars and Constellations in Astrology , Vivian E. Robson, 1923)