The first-ever series produced motorcycle was among the sales at Bonhams Important Pioneer, Vintage and Collectors' motorcycles at the weekend (April 25).
The Hildebrand brothers, Heinrich and Wilhelm, were among many engineers to experiment with steam power, later turning it into a two-stroke gasoline engine.
In partnership with Alois Wolfmüller and his mechanic, Hans Geisenhof, the quartet succeeded in producing a water-cooled, four-stroke parallel twin capable of displacing 1,488cc - still the largest power unit ever fitted to a motorcycle, until recent times.
There had been steam-driven "boneshakers" on both sides of the Atlantic in the 1860s and Gottlieb Daimler's gasoline-engined Einspur of 1885; but nothing before quite like this...
The Hildebrands were in the cycle business so their new engine was mounted in a bicycle frame of the newly developed 'safety' configuration.
When this proved insufficiently robust, a more integrated arrangement was devised, based on that of the Hildebrands' defunct steamer, and the name "motorrad" registered for the new invention, which was patented in January 1894.
H&W's motorcycle was greeted with considerable enthusiasm and plans were drawn up to build a factory in Munich to produce it.
The example offered at Bonhams had been in the ownership of the vendor's family in the USA since at least the early 1930s, which is when it last ran.
Auctioned with an estimate of £40,000-60,000, this essential piece of motorcycle history by H&W sold for £86,200, inclusive of buyer's premium.
And bidders curious to see what the 1894 Hildebrand & Wolfmüller looked like prior to the ravages of time had to look no further than elsewhere in Bonhams' sale.
An 1894 Hildebrand & Wolfmüller full-scale recreation, lovingly hand- built by Mike Kron, a German engineer, sold for £29,900 also included buyer's premium.
One of 15 replicas created, it is based on careful technical and historical research and inspection of the few Hildebrand & Wolfmüllers still in existence.
Meanwhile, a similar 1896 Hildebrand & Wolfmüller motorcycle can be seen in the above video.