The Antwerp-based company supplied engines to many early motorcycle manufacturers in the United Kingdom, among them BSA, Chater-Lea, New Hudson and OK Supreme. Longer list here: Minerva of Belgium
1903. D. Citroen of 45. Holborn Viaduct, London. E. C. advertised Minerva Motors, 2 HP Standard Size. Also 1¼ Romania for vertical position and 2¼ Minerva (1902 pattern)
David Citroen was the driving force behind the export of Minerva engines, and as a result a good many Australian motorcycle makers mounted these engines. From 1901 complete engines were exported to Australia, and later they were built there by A.G. Healing Ltd, under license, until 1910.
Also referred to as David Citroën, he was a cousin of André Citroën, the founder of the famous French marque. In 1900, David Citroen employed a salesman in London who raced Minerva cars and introduced many new clients to the fold. He became quite well known as a champion driver and rather moreso for later endevours. His name was Charles S. Rolls. 
Sources: Wikipedia NL, Graces Guide, et al.
D. Citroen, 45, Holborn Viaduct, E.C.
Minerva motors are this year displayed on a well-designed and somewhat ornate stand, and an excellent, effective show results. The motors shown are the new 2 h.p. Minerva, the 2.5 h.p. Minerva, and the 1.75 h.p. Romania.
The new 2 h.p. engine is full of improvements. The notable alteration is in the mechanical operation of the inlet valve, which, although opinions may differ, is unquestionably an effective, reliable and efficient method for the induction of the gas. We notice one point to which attention has not yet been called, and that is that the valve stems are lifted by a plunger working in a straight line and not at right angles, as in the earlier pattern engines. The new engine has a plug in place of the compression tap, has the sparking-plug immediately over the inlet valve, has all angles removed from the exhaust pipe, and is fed through a very neat and simple spray carburetter. A milled-headed nut permits of throttling of the engine, but this is open to improvement, so that it can be worked by a lever. For those who like to drive on the exhaust valve, it is open to fit a Bowden exhaust lifter. The lifting of the valve in order to free the engine is provided for in the present design by the full retardation of the contact breaker. The absence of the lower radiating ribs vastly improves the appearance of the motor.
In the 2.5 horse-power engine no changes have so far been made, but later on in the new year the mechanically-operated inlet valve will be introduced.
The new Romania engine is on old Minerva lines, fed through a spray carburetter, and with a hand lever for lifting the exhaust valve. The motors are all shown in working section, so that even the novice can gain an excellent idea of the motor system. Despite the introduction of their own engines by many motor-bicycle makers, the Minerva engine enjoys even a greater popularity than ever, for it is to be found throughout the show.
Motor Cycling, 26th November 1902
Minerva Motors, Ltd.
As may be expected, the show of Minerva Motors, Ltd., is a distinctly fine one. The chief features this year are the torpedo-shaped tanks, which hold two and a quarter gallons of petrol. In the case of the 3 1/2 h.p., a new type of Eisemann high-tension magneto is fitted, in which the high-tension winding is carried on the armature, there being no separate coil. Thus the exposed wiring has been reduced to a minimum, diminishing the risk of the short circuits and also rendering the ignition apparatus much more compact. The standard carburetter for 1908 is the G. and A., which is entirely automatic, the air being delivered in correct proportion to the gas by different sized balls being drawn up by the suction of the engine.
Another innovation is the fitting of a petrol strainer, which is a small yet important detail. In the case of the twin, to which accumulator ignition is fitted, there is an ingenious arrangement consisting of terminals carried outside the case, on to which semi-circular springs are screwed. The ends of these springs are drilled, and the holes fit on to the terminals of the accumulator, so that when the case is closed these springs serve not only as electrical connections, but also serve to hold the accumulators firmly in position. The handle-bar controlled contact breaker is also a decided improvement, and ...
Minerva Motors, Ltd.
40 Holborn Viaduct, London, E.C. Stand No. 115.
There is but little alteration in Minerva machines for the coming season. Prices have been lowered all round, and are now, 2¾ H.P., £36; 3½ H.P., £37; 4½ H.P., £45; 8 H.P., £48 10s. All machines are now fitted with Bosch magneto as a standard, and accumulator ignition is now only supplied to special order. The back wheel band-brake can be applied either by back-pedalling or by a small pedal placed close, to the foot-rest, so it earn always be applied instantly whichever position the foot may be in. The Minerva, was one of the very first reliable motor-bicycles on the market, and it has always maintained its original high reputation. We consider that the machines on this stand are typical of the best standard type of motor-bicycle, for they have all up-to-date features, are well made and finished, and are quite free from anything which could be described as faddy.
Stanley Show 1908
Cycle and Motor Trades Review, 1908.
N.B. Another of the Rolls, Royce and Bentley trio features strongly in the history of motorcycling. Born to Australian parents, W.O. Bentley was a very successfull motorcycle racer who, in the days of cast iron pistons, introduced Rolls Royce to the wonders of aluminium.
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