Minerva was a Belgian firm active from 1902 to 1938 and a manufacturer of luxury automobiles. The company became defunct in 1956.
Minerva started out manufacturing standard safety bicycles in 1897, before in 1900 expanding into light cars and “motocyclettes”, particularly motorized bicycles which were a forerunner of motorcycles.
They produced lightweight clip-on engines that mounted below the bicycle front down tube, specifically for Minerva bicycles, but also available in kit form suitable for almost any bicycle. The engine drove a belt turning a large gear wheel attached to the side of the rear wheel opposite to the chain.
By 1901 the kit engine was a 211cc unit developing 1.5 hp, comfortably cruising at 30 km/h (19 mph) at 1,500 rpm, capable of a top speed of 50 km/h (31 mph), and getting fuel consumption in the range of 3 L/100 km (94 mpg‑imp; 78 mpg‑US). These kits were exported around the world to countries including the United Kingdom, France, Germany, the Netherlands, Australia, and other British territories of the time.
As engine power increased, frame ruptures became increasingly common, and by 1903 Minerva had developed an in-frame design for their bicycles, with the engine mounted above the bottom bracket, while still also offering the clip-on kit. From 1904 Minerva began focussing more on car production, and while development and production of the Minerva motorized bicycles and motorcycles continued through to about 1909, they increasingly became a less significant part of the company.