Robot 2 was a robot Solomon bought cheaply from a concession on Illyria Seven.
Biography
Solomon used Robot 1 and Robot 2 to kill the Silurians on the Silurian Ark but got mortally wounded by the dinosaurs on board. The robot took care of him, but were unable to mend his legs. In 2367, Solomon discovered the Eleventh Doctor, Rory Williams and Brian Williams on board. He ordered the robots to take them to him and threatened to have Brian killed if the Doctor didn't mend his legs. When Solomon took Queen Nefertiti of Egypt, the Doctor deactivated the robots while he bargained for Nefertiti. (DW: Dinosaurs on a Spaceship)