This page will describe how units are organized in the Basic Game Rules.
One or two horse combat pieces comprise a troop which is the smallest horse unit used in the game. Since there must always be a command capability present, a single combat piece troop would need to consist of an integrated command piece by itself.
Two troops are combined to make a squadron. While the term comes into its’ own in the next century it was certainly used in the 17th century often referring to each single line abreast formation of multiple troops.
A horse regiment is made up of two or sometimes three squadrons (although a single squadron may be treated as a regiment if a senior line command (officer – cornet) piece is present). The second and third squadrons are commanded by a junior command piece (cornet – trumpeter).
A horse brigade is often simply the wing of the army to which a horse regiment is deployed, with no particular rule as to how many horse regiments the wing might contain. In normal practice the horse was near equally deployed to both the left and right wings. In the later years of the wars, horse began being organized in brigades of three or possibly four regiments. At Dunbar in 1650, for example, the English brigaded their horse while the Scots maintained the older wing organization even though they had a larger number of horse regiments.
As with the foot, A horse wing commander will always command the first brigade and may have two subordinate field command pieces each with a brigade of horse.