Lancers were armed with a lance approximately four meters long, and lancer himself had to a an outstanding horseman, seeing as he made his attack at full gallop.
This limited the employability if lancers, who could only develop their strength – an attack at speed – on flat, hard ground. Cuirassiers, on the other hand, could be deployed both offensively and defensively on terrain that was more difficult to negotiate, and their style of combat required less practice and horses of lesser quality. Cuirassiers attacked only at trot. In January 1597 the Dutch lancers were transformed into cuirassiers. This change was effected almost simultatneously in the Spanish army (comment, who about the battle of the Dunes 1600). The Ordre of 1596 (repeated in 1599 Ordre) prescribed that these cuirassiers had to ride 'strong, stallion-like' horses (that is stallions and geldings perhaps) and be furnished with 'bullet-proof' cuirasses, a visored helmet, arms guards, a bridle gauntlet, a short sword fit for cutting and thrusting, and a pair of wheel-lock pistols [... ] Match (of Matchlock gun) scared the animals and it was difficult to reload the pistol while holding a smouldering match in one's fingers on a nervous horse.
To compensate for the extra weight they were not required to carry their baggage on the back of their own steeds. This was the task of the 'bidets', servants mounted on small packhorses (bidet being the French for a 'nag') who were also responsible for gathering the forage. These bidets were expected to take part in battle, but in practice were 'usually a hindrance and detrimental when one has to fight because of running and fleeing of the boys' . Simon Stevin therefore advocated replacing the bidets with dragoons, 'these being foot-soldiers on horseback.' These lightly could transport the baggage of the cuirassiers and fetch forage for the horses just as well.
Stevin's recommendation to establish the regiments of dragoons remained
unheeded until the 2nd half of the XVII century, but their task was in part performed by the arquebusiers. These were mounted infantry equipped with a visorless helmet (morion), a cuirass, a sword and a wheel-lock carbine. A carbine was a firearm with a length of 'three big men's feet' (c.90cm) and a calibre of 17mm. The relatively short barrel made it possible to load and fire a carbine while in the saddle.''
The attached images are from the late XVI century, or the early to mid period of the 80 years war, as the Dutch-Spanish conflict was known.