1100 people shared risk, investing the equivalent of $300,000 2020 US dollars, into a pool of money larger than ever had been available, opening up new opportunities for what the company could do, and the company became the largest company in the world.
This was the first time (basically) company risk was shared this way, by offering a large amount of tradeable shares.
Previously, people would invest the same amount in a trading ship, but the risk wasn't shared, so if the ship didn't come in, all was lost.