The steam tractor was invented in 1858. Thomas Aveling was the first person to mount the steam engine on a "tractor" frame. Thomas Newcomen and James Watt invented the steam engine.
John Froelich was the person to put an internal combustion engine on a tractor. Froelich tractor was built from a Robinson chassis and he put his gear box behind it which controlled the tractor. John received a patent in 1892.