William, 1st Earl of Dalhousie, raised the regiment mainly from East Lothian in 1643. Moving south in the Spring, it was at York where the defenders on a sally, broke out and attacked the horse lines of the regiment. At Martson Moor, it was in the Fairfax's second line, but routed when it broke and Ruperts Cavalry pushed victoriously through.
After the battle, they joined the siege of Newcastle before moving north to join Argyll around Aberdeen. However, by the early spring they had returned south, serving at the siege of Carlisle. Again it was attacked by a party making a sortie from the city, receiving the worst of it.
After Carlisle fell, they moved south to Hereford but were recalled to join Leslie as he moved to confront Montrose. Engaged at Philiphaugh, they stayed in Scotland but by Christmas were in a sorry state with only one in three troopers having mounts.
Back in England for 1646, the regiment saw little action. As with other regiments, idleness resulted in indiscipline. By 1647 it had a reputation for adultery and fornication. One soldier was charged by fathering a bastard, with his accuser, Margrett Elder saying she had been tied against her will to a post. However, on further questioning both admitted it had been consensual, resulting in both doing public penance (whether she was still tied to the post wasn't mentioned).
Disbanded in 1647, one troop was incorporated in Sir Mungo Murrays' "New Model" regiment of horse.
I wasn't sure how this regiment would turn out - was skeptical right up to the last moment - but when I put the lances in their hands they really looked the business. Might be worthwhile increasing the size to 18….