As Robert Baratheon marched to raise the stormlands and the Reach for the rebel cause, Lord Mace Tyrell called his own banners for King Aerys and led a great host out of Highgarden to meet him. The two armies came together near the town of Ashford, but it was not Mace Tyrell who won the day. His vanguard, commanded by Lord Randyll Tarly of Horn Hill, reached the field ahead of the Tyrell main body and fell upon Robert before he had gathered his full strength.
Tarly, reckoned by many the finest soldier in the Reach, broke the rebel line and forced Robert to abandon the field, dealing him the lone defeat he would suffer in the whole of the war. Robert withdrew northward with the survivors, and Mace Tyrell turned his host toward Storm's End to lay it under siege. The victory belonged in truth to Randyll Tarly, though it was Lord Tyrell who claimed the honor of it, and the grievance of that stolen credit was said to linger between the two men for years after.