Other enactments were passed during this reign with a view to obtain more powerful horses. It was enjoined that every bishop and duke was to keep seven entire horses, each above three years old and not less than 14 hands high; those failing to obey this law were subjected to heavy penalties. Every clergyman holding a benefice of £100 per annum, and all those whose wives wore French hoods or velvet bonnets, were liable to a fine of £20 unless they kept one stallion " and kept and rode upon stallions not less than 15 hands high". Edward VI passed a law prohibiting the importation of stallions less than 14 and mares less than 13 hands high, and horse-stealing was made a felony. It is certain, therefore, that in 1550 great attention was bestowed by Englishmen in attempting to secure a better type of horse than had previously existed in the country. Yet the progress to perfection was very gradual, since we learn from Blundeville, who lived in the days of Elizabeth, that two classes of horses existed, "very indifferent, strong, slow, heavy-draught horses, or light and weak". Moreover, it is a notorious fact that during this reign horses were scarce. Whether this was owing to the destruction of the " unlikely tits" or some other causes cannot be determined, but history informs us of the scanty and meagre display the British cavalry made at Tilbury Fort when assembled there to be inspected by Elizabeth; and Carew in his History of Cornwall suggests that it was to the wholesale slaughter-laws of Henry VIII that the almost total loss of small horses was attributable, " formerly so common in that part of England and Wales ".

During the Plantagenet and the Tudor periods two classes of horses existed in England, "running horses" as they were called, and war or tournament chargers; but the great horse of the past was as inferior to the Shire horse of to-day as the Barbs and Arabians of the Stuart epoch would be to the thoroughbreds of this era. During the reign of the first Tudor the demand for great horses was on the wane; battles being fought with artillery rendered heavy armour defenceless, and led to the employment of armour of a lighter description. This, however, was only partially adopted, and then more for ornament than use. Ladies of high rank who had been accustomed to ride by the side of gentlemen on pillions soon discontinued this practice after the appearance of carriages, which were introduced by the Earl of Arundel in 1580. Heavy horses, no doubt, were primarily attached to these cumbrous vehicles. Their novelty attracted the attention of the rich, which ultimately led to better designs in the construction of coaches, and as they were made to decrease in weight the demand for lighter horses increased. During Elizabeth's reign the days of the tournament were drawing to a close, consequently one of the incentives to the propagation of heavy horses was vanishing away. Whether the discontinuance of this pastime or the introduction of carriages assisted in causing the decrease in the horse supply which was noticed in the scanty display of cavalry at Tilbury Fort, it is impossible to determine. We know that at this time private race-meetings were instituted, to be followed later by public ones, and that "nags" were in demand, and although carriages had been introduced they were used only to a very limited extent. Ben Jonson tells us how the grandees rode on horseback to the theatres, and that when the great Shakespeare fled to London, from terror of a criminal prosecution, his first expedient was to wait at the doors of theatres and hold the horses of those who had no servants, in order that they might be in readiness for their owners after the performance. In this capacity he became so conspicuous for his careful attention that in a short time all who alighted called for William Shakespeare, and scarcely anyone was trusted with a horse if William's services could be obtained. Accordingly he hired boys to act under his orders, who were called Shakespeare's boys, and for years afterwards those who took charge of horses at the doors of theatres were known as Shakespeare's boys.

At this period a more active breed of horses began to be propagated as the effect of causes previously narrated, such as the disuse of heavy armour. This gave rise to the cultivation of light " nags ", the existence of which, a year after the Spanish Armada, Sir John Smythe deplores. He writes: " Their horsemen, serving on horseback with lances or any other weapon, think themselves well armed with some kind of head-piece and a collar, on a deformed, high-bellied beast". As the occupation of the great tournament horse was "going ", its propagation in great measure was discontinued; yet an incentive to the breeding of stout horses still existed, as such animals were required to draw the lumbering and heavy vehicles of this era across countries and plains, over bad roads or where none existed. During the Stuart dynasty consignments of large horses continued to be imported from Flanders and Northern Europe, together with Barbs, Turks, Persians, and Arabs, which by intermixture with our native breeds and between themselves succeeded in forming the ancestral stocks from which all British equine breeds have emanated.

The British cart-horse's descent can be traced from the great horse originally imported from Flanders and Lombardy, but much improved since those days by judicious crossing and careful selection of parents. The Stuarts first introduced quality, but size was wanting; for when William III ascended the throne, and sought to drain the Lincolnshire Fens, he found that the British cart-horse of this date was not strong enough for the tasks imposed upon him; consequently he imported large Dutch horses (the old Lincolnshire Blacks). The Dukes of Ancaster also brought over to this country similar breeds from Holland. This was the first step of any note which gave an impetus to the improvement of our coarser equine stock, and formed the main root from which our cart-horses have proceeded. Our grandfathers have told us how their fathers expatiated on the merits of those horses, of their size and feats of strength, how the blacks with white legs and blazes were most esteemed. These animals or their descendants in time became located all over England, and thus a good cross of fresh blood found its way to the descendants of the old tournament horse, and procured that increase in size and strength for which our present breed of cart-horses are so celebrated.