Three Towers was the seat associated with Lord Costayne, a Reach lord whose allegiance to Rhaenyra and military action against Lord Ormund Hightower’s advancing force placed the location within the southern struggle of the Dance of the Dragons.

Lord Costayne’s Allegiance

After the fall of Harrenhal and defeats at the Burning Mill and Stone Hedge, support for King Aegon weakened across the Reach. Lord Costayne of Three Towers was among the lords who declared for Rhaenyra, alongside lords from Uplands, Horn Hill, Goldengrove, and Greyshield. His allegiance was part of a broader shift that challenged the Greens in a region they had considered one of their strongest sources of support.

Three Towers in the Campaign

Lord Costayne later advanced from Three Towers to attack the baggage train of Lord Ormund Hightower, who had marched from Oldtown with a large host to suppress rebellions in the Reach. At the same time, Alan Beesbury and Alan Tarly harried Ormund’s force, while a host led by Thaddeus Rowan was gathering near the Mander. Faced with these threats, Ormund concluded that he could not continue without support from King’s Landing and requested dragons. Three Towers thus appears not merely as a place named in the roll of Rhaenyra’s supporters, but as the point from which Lord Costayne took direct action against the Greens’ campaign.