House Strong of Harrenhal

The Strongs were among the oldest lineages of the Riverlands, descended from First Men settlers along the Trident. When Aegon Targaryen landed in Westeros, the house chose to back his cause in the war against Harren the Black, the lord of Harrenhal who had promised his rebellious bannermen's daughters in marriage to whoever slew the invading dragon.

That early loyalty paid off. Ser Osmund Strong went on to serve as Hand of the King to Aegon I, the fourth man to hold the office, and kept the post for seventeen years, a tenure none of his predecessors had matched.

The house's real rise came under Jaehaerys I Targaryen, who handed them Harrenhal and raised Bywin Strong to lordship. Bywin was the brother of Ser Lucamore Strong, a Kingsguard knight who lost both his post and his honor when it came out that he had secretly married three different women for years and fathered sixteen children by them.

Bywin's son, Lord Lyonel Strong, thrived under Viserys I, first as Master of Laws and later as Hand of the King. His own son Larys, called Clubfoot, became Master of Whisperers, a post that suited his taste for intrigue perfectly.

Harrenhal's heir, Ser Harwin Strong, took up the role of Princess Rhaenyra Targaryen's sworn shield in 114 AC. His build and the color of his hair fed rumors that he, not Prince Laenor Velaryon, had actually fathered Jacaerys, Lucerys, and Joffrey.

The year 120 AC cut that chapter short: Lyonel and Harwin died together in a fire that tore through Harrenhal. The title then passed to Larys, the younger son, who became the castle's new lord.

When the war over the succession broke out, House Strong sided with King Aegon II, but the castle ended up falling into the hands of the Black faction. Harrenhal then became bait: Daemon Targaryen left it to join the taking of King's Landing, leaving the fortress half-empty.

Prince Aemond Targaryen took the bait and occupied the castle, but on finding Daemon already gone, he turned his fury on those who had handed it over. He accused House Strong of treason for surrendering Harrenhal and blamed Lord Larys directly for helping bring down the capital.

Aemond's resentment over being duped fed on old suspicions about the true parentage of Rhaenyra's sons, and the Strongs left in Harrenhal paid for it one by one. He killed Ser Simon Strong, the castle's castellan, with barely any effort, and with him nearly every other member of the house.

He spared only Alys Rivers, a Strong bastard whom he took as his lover. After Aemond's death, she was the one who ended up seizing control of Harrenhal, and it was said she bore him a son.

Larys Clubfoot, the last living Strong, survived the war but not its aftermath: during the Hour of the Wolf he chose death over taking the black at the Wall, and the house died with him.

Long after the house had died out, two men calling themselves Duncan and Denys Strong served in the Golden Company and swore loyalty to Prince Aegon Targaryen before the company sailed for Westeros. In a mercenary company anyone could take whatever surname they liked, so there's no guarantee either man was an actual descendant of the Harrenhal line.