Any planet which might appear in the first house….no matter what sign ends up there, manifests in an Aries-like manner. So, for example, if you have the Moon in Libra in the first house, it will be affected by the house position and be more Aries-like than a Moon in Libra in the seventh house, the natural house of Libra.
There is so much to know when learning astrology that one can feel overwhelmed. I suggest you start by learning the archetypes of each house.
Follow this by learning the signs, then the planets.
Eventually, you will be able to combine the archetypes. For example, I have Virgo in the first house, so my Virgo is a little more aggressive and independent (yang) than the natural (yin) Virgo which is in the sixth house. Combining the archetypes in this way adds a deeper level to chart analysis.
It follows that a person with Sun in Virgo in the first house will be different from a person with Sun in Virgo in the sixth house (or any other house for that matter). That Virgo Sun person (1st) will appear more outgoing and confident than one would expect from the definition of Virgo. They will be more Aries-like.
This may explain why the Sun sign horoscopes we find in the newspaper may seem odd. You look for your Sun sign, read what’s there and say…Huh? If you know the house your Sun is in, you might also look in the sign for that house. That will give you a little more information.
My Sun is in Gemini and is in the 10th house, the natural house for Capricorn. It follows that my Gemini Sun has some Capricorn-like qualities.
Pluto/Mars (modern ruler/traditional ruler)
Uranus/Saturn (modern ruler/traditional ruler)
Neptune/Jupiter (modern ruler/traditional ruler)