Like all scientists and engineers, roboticists stand on the shoulders of those who came before. That means they learn from earlier work and build on it.
The work of roboticists started in ancient Greece with Pygmalion, a character in mythology. He created an ivory sculpture of a woman and fell in love with her. Aphrodite, the Greek goddess of love, turned the sculpture into a real person for Pygmalion to marry. And there she was, the first humanoid machine, even if only in the imagination.
Jump to the late 15th century, when artist Leonardo da Vinci built a knight that could move its arms and mouth with the help of pulleys and gears. From there, the story continues. One development keeps building on another. That’s how science and engineering work.