The patent system developed to protect people’s inventions. The system we know is said to have its routes in Venice, with the Venetian Statute of 1474. The decree by which new and inventive devices, once they had been put into practice, had to be communicated to the Republic in order to obtain legal protection against potential infringers.
The idea of patents dates back to Greek times, with discovered text relaying that:
encouragement was held out to all who should discover any new refinement in luxury, the profits arising from which were secured to the inventor by patent for the space of a year
This early reference is a clear example of the point of the patent system. For the individual, patents provide a way to profit from being inventive, making it worthwhile financially to come up with new ideas and inventions to improve life.
But more importantly, for society the patent system provides a reason for those who do come up with new ideas and inventions to improve life, to share them.