The Doctor did not want to stay on Gallifrey any longer, so he "borrowed" an old Type 40 TARDIS. In the TARDIS he and his granddaughter Susan Foreman left their home planet Gallifrey. They stayed for a time on Earth in the 1960s, where Susan also went to school. Her teachers, Barbara Wright and Ian Chesterton, discovered the TARDIS. They traveled for a while with the Doctor, and returned to Earth two years later. After them the Doctor often took other people with him on his travels.