The Sun was born in a vast cloud of gas(nebulae) and dust around 5 billion years ago. Indeed, these vast nebulae are the birth places of all stars. Over a period of many millions of years, the gases and dust combined to a common center under its own gravity. It became hotter and hotter and eventually, reached a temperature of around 1 million degrees, its core ignited, causing it to begin nuclear fusion. When this happened, the Sun began producing its own light, heat, and energy.
The Romans called the sun Sol, which in English means sun. In ancient Greece, the sun was called Helios.Thus our system of planets is called the Solar System.