It is understood that the first commercially successful light-weight, petrol-powered, general-purpose tractor was built by Dan Albone, a British inventor in 1901, who eventually formed Ivel Agricultural Motors Limited.
The company built a 3-wheeled lightweight tractor powered by a 2 cylinder gasoline engine of 8 hp (6.0 kW), that sold for £300, a considerable sum in the 1900s; it continued building tractors until it ceased trading in 1920.
In this video, you can see this historic tractor at work, harvesting oats with a binder in Moynalty steam threshing festival, Co. Meath.
Video source: Videos of Irish Farming Life Youtube