The Third House signifies the native’s siblings, both brothers and sisters, along with his extended family and neighbors. It governs short journeys, movements within the homeland, letters and messages, and local communications.
The Ancients called it Thea—meaning the Goddess—because it relates to happiness and familiarity, such as the joy one might take in kindred and close companions. Indeed, people tend to trust those they know—siblings, kin, and neighbors—more readily than strangers. Yet, experience shows us that at times, a stranger may become a truer friend than a brother, and a brother may behave as if he were a stranger.
This is a cadent house, removed from the angles, and in the human body it corresponds to the arms and shoulders.
Planets in the Third House
Saturn (♄)
When Saturn is in the Third House, it brings trouble and danger to the native’s siblings and breeds hostility or estrangement between them. The native may suffer harm or hardship during short journeys, face obstacles in daily affairs, and may show dishonesty or deceit, especially in matters of faith and religion. He may become hypocritical or duplicitous in character.
Jupiter (♃)
Jupiter here brings good fortune to the native’s siblings and extended family, fostering harmony and mutual respect. The native will take pleasure in short journeys, finding them profitable and peaceful. This placement also inclines him to religious devotion, honesty, and a pure conscience.
Mars (♂)
Mars in the Third House often leads to conflict with siblings, even to the point of hatred or violence. The native may fall into danger during short journeys, including robbery or physical harm. Siblings may be stubborn or lawless, and at times, their deaths may be signified. The native may be impulsive, irreligious, or blasphemous, and prone to attacking sacred things.
If Mars is in Aries or Scorpio here, the native may become dangerously violent—even capable of fratricide. When Mars is placed in signs ruled by Jupiter, he brings wealth and activity; in signs of Saturn, he reveals hidden treasures; and in signs of Venus, he indicates many siblings who bring joy.
If Mars is in Leo with the Moon, the native may suffer loss through thieves. But if Mars is in his own sign and afflicted by Mercury, it can signify the death of a brother by the native’s own hand. In all cases, Mars here brings much toil to the native.
Sun (☉)
The Sun in the Third House indicates that the native has noble siblings and enjoys favorable short journeys. He may receive appointments, honors, or gifts from princes and high officials. Yet, due to his religious convictions, he may at times be imprisoned or constrained.
Mercury (☿)
Mercury here gives the native a love of truth and religion, and he is inclined to avoid error. His siblings are well-spoken, polite, and there is affection between them. Short trips will be pleasant and productive.
Mercury also lends a gift for mathematics, and a keen, inventive mind. If well aspected by Jupiter or Venus, the native thrives in religious or intellectual pursuits, and has helpful siblings. If Mercury shares qualities with both Jupiter and Saturn, the native becomes a brilliant scholar, filled with creative insight and capable of new inventions.
When Mercury is with Venus, especially in Libra or Gemini, the native may become an accomplished musician, and from youth be drawn to wisdom, learning, and moral refinement.
Moon (☽)
The Moon here shows many siblings, and frequent, pleasant journeys often taken in their company. The native receives benefit from religious kin, and may be given a position of trust by noble persons, which brings both honor and wealth.
North Node (☊)
The Dragon’s Head in the Third House makes the native pious and religious, bringing success through spiritual means, as well as fortunate journeys and noble siblings.
South Node (☋)
The Dragon’s Tail here causes misfortune in travel, and trouble or danger to siblings and kin. There is often quarreling, discord, and even plots or attempts at harm between the native and his relatives.
Lot of Fortune
The Part of Fortune in the Third House indicates many journeys, often prosperous and sacred in nature. It inclines the native toward religious visits and brings gain, virtue, and delight in honesty and piety.
Rulers of Other Houses in the Third House
Lord of the First in the Third House
When the ruler of the Ascendant is in the Third House, especially in a fruitful sign, it indicates the native will have many siblings and be naturally inclined to travel. If the planet is well placed, these travels and familial relations bring prosperity; if afflicted, they result in loss or hardship.
Lord of the Second in the Third House
This shows the native may gain wealth through short journeys, errands, or local dealings. However, it also suggests loss through siblings and misfortune in their financial affairs. The native’s brothers may struggle to prosper.
Lord of the Third in the Third House
Here the native is drawn to frequent journeys, not merely out of necessity but for the pleasure of the body and mind. It signifies that he will have many siblings and extended kin, and there may be a strong bond with them.
Lord of the Fourth in the Third House
This placement grants property or inheritance to the native, gained through siblings, kindred, or local travels. However, since the third is the twelfth from the fourth, it also shows that the native’s siblings may suffer loss or misfortune through their parents or family heritage.
Lord of the Fifth in the Third House
This suggests that the native’s children will receive benefits from the father’s relatives or from close friends. Since the third is the eleventh from the fifth, it shows that social and familial connections support the well-being of his children.
Lord of the Sixth in the Third House
If the sixth house ruler is placed in the Third, the native is prone to illness during travel, particularly in short or routine journeys. It also shows that the siblings may be sickly, weak, or plagued by health troubles.
Lord of the Seventh in the Third House
This often points to a marriage with someone related by blood or family ties. If the planet is well dignified, such unions are friendly and peaceful. If not, the native may experience quarrels, disputes, or even hatred with both spouse and siblings. Some traditions report: “A brother may lie with the native’s wife.” This placement often kindles discord within the family circle, especially involving marriage and in-laws.
Lord of the Eighth in the Third House
This denotes that the native’s siblings are poor, sickly, and may suffer shame or disgrace. Their lives may be short, and the native himself may be in danger of death or misfortune during travel, especially on routine or short journeys.
Lord of the Ninth in the Third House
This indicates the native is respected by his siblings and extended family on account of his religious faith or knowledge. He may also travel frequently, and gain favor or profit through religious people or institutions.
Lord of the Tenth in the Third House
This placement shows the native may have few siblings, but those he does have will be honorable and held in esteem. He will undertake many short journeys and gain both honor and material benefit from them.
Lord of the Eleventh in the Third House
This position bestows upon the native noble, wealthy, and well-known siblings. It also brings good fortune in short journeys, with success in errands, communication, or dealings close to home—especially if the planet is well dignified.
Lord of the Twelfth in the Third House
In this position, the twelfth ruler makes the native’s siblings into adversaries, or at least there is deep disagreement between them. His brothers may also suffer many enemies, and the native is likely to face trouble, loss, or betrayal during short trips, especially due to the actions of hidden foes. Grief and toil, particularly tied to material concerns, will follow him.
From the The Doctrine of Nativites and Horary Questions, JOHN GADBURY