This is Part 12 in a series of posts depicting the battle of Guilford Courthouse in miniature. Previous posts: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9, Part 10, Part 11.
The 2nd Battalion of Guards was one of the first British units to reach the American third line. They attacked and quickly defeated the 2nd Maryland Regiment. In their pursuit of this regiment, the Guards then captured a battery of guns and gained the American flank and rear (Part 10). This success on their part was short-lived. Moments later they were suddenly counterattacked by the 1st Maryland Regiment and charged by Lieutenant-Colonel William Washington’s light dragoons.
Lieutenant-Colonel John Eager Howard of the 1st Maryland Regiment recalled:
Our men gave them some well directed fires, and we then advanced and continued firing. At this time [Colonel John] Gunby's horse was shot… his horse fell upon him, and it was with difficulty he extricated himself. Major [Archibald] Anderson was killed about this time. As we advanced I observed Washington's horse, and as their movements were quicker than ours, they first charged and broke the enemy. My men followed very quickly, and we passed through the guards, many of whom had been knocked down by the horse without being much hurt. We took some prisoners, and the whole were in our power. 
Lieutenant-Colonel Henry Lee, in his history of the southern campaign, wrote that “Gunby… wheeled to his left upon [the Guards]… Here the action was well fought; each corps manfully struggling for victory; when lieutenant colonel Washington… pressed forward with his cavalry… This combined operation was irresistible… the two field pieces were recovered” and the Guards were “driven back with slaughter”.
From the third line, looking west (here and below, click to enlarge). In the foreground, the 2nd Battalion of Guards melees with the 1st Maryland and William Washington's light dragoons. In the middle ground, British infantry, artillery, and cavalry approach the third line. In the extreme distance lie casualties from the fighting on the first and second lines.
A view of the third line fighting looking south. The 2nd Guards are being mauled at upper left, while other British units approach from the right. At center, the 2nd Virginia Regiment occupies a hillside opposite the 33rd Regiment of Foot.
The 1st Maryland Regiment drives the 2nd Battalion of Guards into the open field.
Washington's light dragoons pursue the remnants of the 2nd Guards.
Most of the Guards were left prostrate on the field of battle, but a number reached the western edge of the field. Lee believed these men were “saved by the British artillery". He wrote that these guns:
“to stop the ardent pursuit of Washington and Howard, opened upon friends as well as foes; for [Lieutenant-General Charles] Cornwallis, seeing the vigorous advance of these two officers, determined to arrest their progress, though every ball, leveled at them, must pass through the flying guards.” 
Neither Howard nor Cornwallis mentioned the British firing on their own men. However, Cornwallis did report that “The enemy's cavalry was soon repulsed by a well-directed fire from two 3-pounders”. 
Hundreds of American militia were in the vicinity of this bloody clash, and it seems some were willing to continue the contest. John Wadkins stated that “some of the militia who had stopped at the Court House followed in the rear of the Horse” when they charged the Guards . James Martin claimed that he helped rally “about 500 [men] & was marching them to the Battle Ground” .
However, Greene had previously issued orders for the army to retreat (see Part 11), and soon these militia began to move off. Martin noted that when he was approaching the fighting “I met General Stephens [i.e., Brigadier-General Edward Stevens] of [the] Virginia [militia] Corps retreating[.] I asked if the Retreat was by General Greene's Orders[;] he told me it was[.] I then retreated with him” .
At the same time that Howard and Washington lost their potential support, the Guards were aided by British troops coming through the woods.
the 71st regiment, which, having been impeded by some deep ravine, were now coming out of the wood on the right of the Guards, opposite to the Court-house. By the spirited exertions of Brigadier-General [Charles] O'Hara, though wounded, the second battalion of Guards was soon rallied, and, supported by the grenadiers [of the Guards], returned to the charge with the greatest alacrity. The 23rd regiment arriving at that instant from our left, and Lieut.-Colonel [Banastre] Tarleton having advanced with a part of the cavalry, the enemy were soon put to flight. 
A challenging aspect of depicting the battle in miniature has involved issues of timing. The sequence of events involving each unit is generally clear, but it’s rather difficult to determine how the events involving one unit corresponded in time with the events involving other units on the battlefield. A source of particular consternation for me has been the retreat of Stevens’ brigade to the third line. In recent posts, Stevens’ men were depicted as reaching the third line only after major combat had begun on the third line (in the second picture, above, they are the block of retreating militia at the top of the image). There are a couple of reasons for this. One is that the 71st Foot is known to have been delayed by rough terrain on its march to the third line (see Cornwallis' quote, above); Stevens’ brigade had to traverse the same ground, and it’s reasonable to think they would have been delayed as well. The other is Martin's pension application (also quoted above), which implies that Stevens’ brigade was still moving towards the courthouse when the Guards were defeated. However, the depiction has ended up looking a bit peculiar – this huge brigade of Virginia militia is shown essentially behind the Guards during the third line fighting. Of course, the alternative would also look a bit odd – having Stevens' brigade reach the third line quickly only to stand idly about while the Guards attacked and routed the 2nd Maryland. (As is, there are already quite a few militia figures shown hovering near the third line, based on Martin’s comment above, and comments by St. George Tucker concerning Lawson’s Virginia brigade ). There is, to say the least, room for varying interpretations.
1. Howard is quoted in James Herring and James Barton Longacre (1835). The national portrait gallery of distinguished Americans, Vol. 2.
4. Lee's and Cornwallis' accounts of the battle (among others) can be found in this compendium
5. Letters of St. George Tucker to his wife (from the Magazine of American History).