German scientist Otto Bayer, who founded the Bayer Company, was the inventor of polyurethane foam, the material from which sponges are made. Bayer invented this material by accident in 1937.
As German scientists persisted in creating uses for polyurethane foam, they created a defective batch that had many air bubbles. The outcome resembled sea sponges, which had been used since the Middle Ages to help wash the body. Prior to that, people used rags to wash dishes.
The earliest polyurethane sponges were easily destroyed during dish washing due to their fragility. As the technology progressed, these sponges were designed to be more durable.