|Title|| High Steward of Highgarden|
Lord Paramount of the Mander
Lord of Highgarden
Warden of the South
|Died||In 5 AC, at Dorne|
|Book(s)|| The World of Ice & Fire (mentioned)|
A Game of Thrones (appendix)
A Storm of Swords (appendix)
A Feast for Crows (appendix)
A Dance with Dragons (appendix)
Harlen Tyrell served as the steward to Mern IX Gardener, King of the Reach, at the time of Aegon's Conquest. After King Mern IX died at the Field of Fire, King Aegon I Targaryen marched on Highgarden, where Harlen yielded up the castle without a fight, pledging his support to Aegon. For this, Aegon named him Lord of Highgarden and gave him dominion over the Reach as Lord Paramount of the Mander and Warden of the South, despite the fact that the Tyrells could only claim descent from Garth Greenhand through the female line, while other houses, with older and more distinguished lineages, had closer blood ties to the now-extinct House Gardener.
Harlen's elevation to Lord of Highgarden caused a number of his bannermen to voice their resentment, who bitterly compained about having to serve an "upjumped steward". However, their complaints were of no avail. Maester Yandel speculates that Harlen Tyrell had been chosen as the new Lord of Highgarden by Aegon I because they had not taken up arms against the Targaryens, whereas the Oakhearts, the Florents, the Rowans, the Peakes, and the Redwynes had marched beside King Mern IX.
Harlen served the Targaryens loyally and proved able in his lordship of the Reach. He marched south in 4 AC beside the Targaryens in the First Dornish War, and fought with King Aegon I against the Dornish mountain lords in the Prince's Pass. He next marched his army to Hellholt, but lost many of thurst and exposure to the sun on the way. After the Targaryens had claimed Sunspear, Harlen was put in charge of putting down revolts. In 5 AC, when Dorne rebelled, Harlen marched with his garrison from Hellholt, aiming on conquering Vaith and retaking Sunspear. However, he vanished with his entire army in the sands of Dorne, never to be found again. Harlen was succeeded by his son Theo.