|Title|| High Steward of Highgarden|
|Allegiance|| House Tyrell|
|Book(s)||The World of Ice and Fire (mentioned)|
Lords Peake and Manderly instigated a civil war to see their respective wives, both daughters to the senile old King Garth X Gardener, succeed as Queen of the Reach. Ser Osmund led an alliance of twoscore houses to put down the rebels and reclaim the ruins of Highgarden, as a Dornish king and his raiders had sacked the seat of House Gardener and killed Garth X.
Ser Osmund placed a second cousin of the late Garth X upon the throne as King Mern VI Gardener. With the counsel of Osmund, Mern VI began the reconstruction of the Reach and Highgarden and the power of House Gardener. Osmund was succeeded by his son, Ser Robert Tyrell.