The 1st Regiment of Dragoons owes its origin to the marriage of Charles II with Catherine of Portugal. The Queen brought as her dowry the island of Bombay and the city of Tangiers. A British garrison was raised to occupy the newly acquired territory, consisting of four foot regiments and a troop of "Horse". The nucleus of the present regiment was therefore ranked first as "Horse". The troop was formed in 1661 by the Earl of Peterborough, and was cuirassed, with pot helmet, pistol, a carbine, and sword. Embarking for Tangiers in 1662 they served there for twenty two years, having many engagements with the Moors. In one of the many partial sieges the place underwent Captain Witham made a dashing Sortie, capturing a Moorish standard of the army of Gaylau, "Usurper of Fez"; but their gallantry was not always so rewarded, as later in the same year the "Tangier Horse" fell into an ambush, where they suffered severe loss, and their leader, the Earl of Teviot was slain.

So formidable were the Moorish enterprises in 1679-80 that the garrison was largely reinforced by a battalion of Guards, another of Dumbarton's Regiment, a fresh battalion, afterwards to be the "King's Own", and six troops of "Horse". To these were also added three troops of Spanish cavalry from Gibraltar. But the King did not feel disposed to pay for the troops himself, and the Parliament would not help him; so the small army was withdrawn to England; but before that it was reconstituted with two fresh troops, the whole being under the colonelcy of John, Baron Churchill, as "The King's Own Royal Regiment of Dragoons". By the time they returned home in 1684 this title had been modified into "The Royal Regiment of Dragoons," and they abandoned the cuirass and their cavalry duties, to be armed with long muskets and bayonets as true Dragoons. The pot-helmet, too, was discarded, the hat having inside a metal skull-piece. Seeing how long their African service was, it is to be regretted that "Tangiers" does not commence their list of recorded regimental honours.

They fought at Sedgemoor, escorted the Duke of Monmouth as a prisoner to London, and were unfortunate in attending as guard to Judge Jeffries at the "Bloody Assize". Their Colonel, Lord Cornbury, early took the side of the Prince of Orange after his landing in Torbay, but his men did not as a body share his enthusiasm. None the less, they were still retained in King William's service, and despatched to the North against Dundee, to be then transferred to the army in Ireland under Duke Schomberg. There they came into personal conflict with Sir Teague O'Regan, one of the Irish leaders. On one occasion a trooper of the regiment having an argument with a priest on a theological point, came to blows with his opponent; but on complaint being made to Teague, he simply replied, "What te de'il had he to do to dispute religion with a Dragoon?" Evidently he thought the argument, like Providence, is "on the side of the big battalions".

They served in the Netherlands in 1692-97, went to Portugal in 1703, joined in the siege of Barcelona, and were made prisoners of war with the rest of the garrison of Brihuega. Notwithstanding all this long and continuous service, the first battle-name on their roll is that of "Dettingen", where they captured the standard of the Black Musketeers. "It was of white satin, embroidered with gold and silver", with a band of arrows, and the motto "Alterius Jovis Altera tela" in the centre. They were also present at Fontenoy, soon after which they returned to England.

As with other cavalry regiments, their clothing and standards were fixed by regulation in 1751. The first, or king's , guidon, was of scarlet silk, with the rose and thistle crowned, "Dieu et mon droit", beneath, and the white horse of Hanover on a red panel in the first and fourth corners, and "I.D." in gold on a red ground in the second and third. The standards of the other troops were blue and the centre contained the lion, surrounded by the Garter and its motto, and a wreath of roses, thistles, and shamrocks, the whole crowned. Later on the eagle was added below, in remembrance of Waterloo. They served again in Germany in 1760, and sailed for Portugal in 1809. The joined in the advance from the lines of Torres Vedras, rescued two guns that had been captured at Fuentes d'Onor, and saw incessant service until the war terminated, well earning the right to count "Peninsula" among their honours.

The regiment shared in the invasion of France, executing one severe march from 2am until 11.30 at night, and formed part of the army of investment at Toulouse, marching to Calais for embarkation after the peace. It was of short duration. The return of Napoleon from Elba recalled the Royal Dragoons to active service, and they were brigaded with the Greys and Inniskillings in the "Union Brigade". They were clad then in light blue pantaloons, with a broad red stripe, short tailed scarlet coats, and leather helmets with brass mountings and a horsehair plume. The girdle was worn for a while, and the sabretasch first appeared. Their first charge at Waterloo was against D'erlon's corps, which threatened to pierce the centre of the British line, but the brilliant dash of the brigade broke and dispersed the corps, capturing the eagle of the 105th Regiment of the Line and 2,000 prisoners. In attempting to carry the enemies batteries on the other side of the ravine, they were met, blown and disorganised, by the French Cuirassiers. The brigade was driven back with heavy loss, and Ponsonby, their brigadier, was slain. The eagle was taken by Captain A.K. Clark, but his claim to the honour was not fully recognised until 1839. He says that as he saw the French retiring, and the bearer of the eagle with it, he "rode at him, calling out 'Secure the colour!' and, at the same time, my horse reaching it, I ran my sword into the officer's right side who carried the eagle, who staggered and fell forward, but I do not think he reached the ground on account of the pressure of his comrades.... As he fell with the eagle a little to the left, I was not able to catch the standard so as to hold it. Corporal Styles and some other men rushed up to my assistance, and the standard was in an instant in the corporal's possession." The corporal carried the colour to the rear, and claiming the credit of the capture, was given an ensigncy. But the true story was recognised in 1838, when Colonel Clark received an augmentation to his family arms indicative of the action, and the regiment was permitted to wear the eagle among its badges. The uniform continued to change. For many years after Waterloo a helmet with an enormous woollen crest was worn instead of that with a horsehair plume worn in 1815. In the Crimea they formed part of the Heavy Brigade under General Scarlett, joining in the charge at Balaklava, and attacking in flank the hostile squadron that threatened to envelop the first line. For this the Royals are authorised to wear the words "Balaklava" and "Sebastopol" on their standards, which in 1858 were no longer carried by each squadron, one being given the entire regiment.

Their only short name is simply "The Royals", though at the close of the last century they were known as the "Royal English Dragoons". The uniform is of scarlet, with facings of blue cloth; the helmet of white metal with gilt ornaments and a black plume.