Lord Paramount Hoster Tully
Within a fortnight of news regarding Maeleys planned invasion of Westeros reached Riverrun, Lord Hoster and his brother Brynden rode for Kings Landing. When the brothers arrived at the capital they found the remenets of the scattered host of the final Blackfyre pretender. Brynden rode them down, giving none quarter. For Lord Hoster's participation in the war the wise King Jaehaerys named Hoster as his Master of Ships, a post which Hoster would serve for some years.
Hoster's plans could not be delayed, nor were many expecting his ruthless pragmatism. Within a year of the wars completion Hoster was wed to Genna Lannister, daughter of the feeble Lord Tytos. Her betrayal would be the only thing Hoster didn't expect.
Lord Hoster sought to expand his influence into the contested land of the Claw. He knew that the King would never allow this, but Lord Darklyn was the Kings Master of Whisperers and would most likely be allowed to expand into the volatile region. And so Hoster invaded South Crackclaw Point, house Crabb put up a nobel defense, yet not much can stop 25,000 riverlander men at arms. Once house Crabb was exiled and their land confiscated Lord Hoster received a message from the King.
By order of the King, you are to relinquish South Cracklaw Barren to the royal authority. - King Jaehaerys II
It must also be noted that 100 men from Duskendale were dispatched to demand that Hoster halt his aggression. All of these men were unfortunately slaughtered by brigands en-route to Riverrun.
Hoster humbly bent his knee and granted a member of house Darke the land he had taken. Within a couple of years when Lord Darklyn attempted to usurp the same land which Hoster had taken. Hoster sought an audience with the King. He argued that if he is not allowed to take the land, then Lord Darklyn should not be allowed as well. The King agreed, and so the ambitious Darklyns were put in check... for a time.
Of course this conflict began a rivalry between the houses of Darklyn and Tully. The son of Alyn Darklyn was a ward of Brynden Tully. Upon hearing that he would be forced to give up the land, Denys was sent to Kings Landing to be fostered by his father in place of Brynden.
The wise King Jaehaerys was beginning to become skeptical of Lord Hoster, and so he ordered that Aerys Tully, the son of Hoster. Was to be fostered in Kings Landing personally by the King. After a couple of years of delaying Aerys arrived in Kings Landing to meet his new guardian.
A year later Lord Hoster's heart was broken. News arrived from Riverrun, Brynden had caught Genna and some Knight fucking in his bed. Brynden swiftly executed the knight and forced Moon Tea down Genna's throat. By the time Hoster arrived at Riverrun the High Septon had accepted his divorce request. Hoster famously stated that "Ser Brynden is the most just man in the Seven Kingdoms."
However, when a trial was held to satisfy the Lords of Westeros Hoster and his brother ran into the issue of finding a witness. Seeing as the only other witness was now being eaten by the fish, Hoster could not find an impartial witness to testify against Lady Genna, and so Lady Genna was released and sent back to Casterly Rock. Where she promptly became ill and died shortly afterward.