The Sun is the centre of the Solar system. All the planets as discovered by Copernicus rotate around the Sun. This replaced the earlier ideas of Ptolemy of the Earth being at the centre of the Solar system. The Sun is the giver of light to all the planets, the heart of the Solar system. Indeed when we talk about conventional astrology and say she is this or that sign we are talking about Sun sign astrology. She is a Virgo would mean the Sun at her time of birth lay in front of the constellation of Virgo. Purely basing Astrology on the Sun Sign tells only a small part of the story as we will see when mentioning the other planets, however that part is very significant.
Without the Sun nothing else would have life. Everything relies on it's energy and power. It is an outgoing masculine yang energy, very different to the Moon as we will see later. Without it we would not have light to see things and be conscious of the different objects that make up our world. Where the Sun shines things become clear and out in the open. Where there is darkness the world is hidden and takes on a very different nature. Like a great emperor all the planets go round the Sun and pay it tribute. Indeed many cultures have worshipped the Sun as the ultimate deity. The Egyptian Pharoah Akhenaten abandoned all the other Gods in favour of the one Sun God, the Akhen. Ultimately the Sun is not the source of all things but without it's influence there would be no life in our Solar system.
As the Sun is at the centre of the Solar system so it is our central creative core. It is how we radiate our life force to the world around us. As it creates life so this is how we express our creative life force. It is a journey as we strive towards expressing this energy of ourselves and it can take people a lifetime to grow into their own Sun. It is the energy of the Quest, to become who we were meant to be and who we could be.
People with a very strong Sun influence are often very generous, expressive, outgoing, energetic, charismatic , confident and flamboyant individuals. They expect to be the king or queen as the Sun is the emperor of the Solar system. The shadow side of the Sun can result in excessive pride, ego , jealousy and stubborness. This is often when the Sun person is not given the recognition they desire.
Both the Sun and the Moon only rule one of the signs in contrast to the other planets that each rule two signs. In this way the energy of the Luminary ruled signs are doubly powerful since they are so concentrated. The Sun rules the sign of Leo which is people born at the height of the Summer in the Western World. Leos are natural leaders of the Zodiac with all the gifts the Sun gives them. Their natural Charisma is rarely rivalled and they regularly make great influences on Society. Napoleon was a famous Leo who turned a whole army sent against him to his cause purely with his Charisma and leadership abilities.