House Strong was a noble house from The Riverlands prior to the Dance of the Dragons. They were granted the castle of Harrenhal by King Jaehaerys I Targaryen and would serve as lords under the rule of King Viserys I Targaryen also. They have since become extinct. Their sigil were three lines of pale blue, red and green on a white background, representing the three forks of the Trident.
House Strong rose their banners with House Tully during the War of Conquest, siding with House Targaryen over House Hoare. They were overlooked for the title of Lord Paramount of the Riverlands. Ser Osmund Strong rose to become Hand of the King for King Aegon I Targaryen. It was Osmund that oversaw the construction of the walls around the capital of King's Landing.
Ser Lucamore Strong was named to the Kingsguard under the rule of King Jaehaerys Targaryen. He was caught breaking his vows aftr fathering sixteen children. As punishment he was gelded and sent to join the Night's Watch. Lyonel Strong was named Lord of Harrenhal after the extinction of House Towers. in 105 AC Lyonel was named Master of Laws by Viserys I Targaryen. He was promoted to be Hand of the KIng when Ser Otto Hightower left the position.
Lyonel's son and heir, the powerful Ser Harwin Strong, was a reported lover of Princess Rhaenyra Targaryen. Harwin and Lyonel died in a fire at Harrenhal in 120 AC, meaning that Larys Strong inherited the castle. Larys eventually rose to be the Master of Whisperers for Viserys.
The house had "not-inconsiderable" wealth by the time of the Dance of the Dragons according to Archmaester Gyldayn. Larys sat on the Small council of King Aegon II Targaryen, leaving Ser Simon Strong as castellan of Harrenhal. Simon surrendered the castle when Prince Daemon Targaryen arrived on the back of his dragon, Caraxes. Larys helped to smuggle Prince Maelor Targaryen and Princess Jaehaera Targaryen out of the capital when Rhaenyra moved on the city.
Aegon II refused to surrender to the armies of Lord Kermit Tully when he moved on King's Landing after the Battle of the Kingsroad. As a result the king was poisoned. Lord Cregan Stark accused Larys of conspiring to kill the king, and as a result Larys was executed during the Hour of the Wolf, choosing death over going to The Wall. His death ended the main branch of House Strong.
A Feast for Crows Edit
Lord Petyr Baelish refers to the extinction of House Strong as an example of what happens to those that rule over the lands of Harrenhal.