How and When Did the Iron Throne Learn about Renly's Betrayal?

Renly was not officially named a traitor in the Sansa chapter. The Iron Throne instead organized a roll call, urging lords and ladies with dubious or undeclared loyalties to pledge their fealty to the newly crowned King Joffrey. This event took place in King's Landing, whereotts Lord Pycelle, clad in a magnificent robe of thick red velvet with an ermine collar and shiny gold fastenings, read a long list of names from a parchment. These individuals were commanded to swear their allegiance to Joffrey. Failure to do so would result in the forfeiture of their lands and titles.

From the names Sansa heard spoken, there are several neutral or ambivalent parties, such as Lysa Arryn and her son, several members of House Royce from the Vale, and even Doran Martell, the Prince of Dorne. If Renly had answered these summons and taken up Joffrey's cause, he would have retained his title and lands at Storm's End. However, Renly's actions and his subsequent betrayal remain a mystery to many.

The Confirmation of Renly's Betrayal

Exactly when the Iron Throne learned of Renly's betrayal is close to the events detailed in the Tyrion chapter, where Tywin Lannister decides to send Tyrion as his Hand to King's Landing to take control. Tywin mentions that Varys had informed him about Renly's actions, such as his coronation and marriage to Margaery Tyrell. This information likely came through Cersei Lannister's letter to Tywin, as Tywin's conversation revolves around Cersei's command to march against Renly.

Reactions to the News

Ser Kevan is clearly shocked by the news. He asks, 'What have they done to Joffrey?' Lord Tywin, with a faint flicker of disdain, responds, 'Remember that it was Varys who told Ned that Renly is gone, and it was likely Littlefinger, or some combination of both.' These informed men, such as Ned Stark and Tywin Lannister, were well aware of Renly's offer to Ned and his plans before they were discovered.

Renly's actions, or lack thereof, reveal a certain hesitancy. Sneaking off with his trusted retainers instead of directly confronting Joffrey suggests that Renly was not comfortable with the direction of the new kingship. This move by Renly is seen as a betrayal, as he fled with his subjects while leaving his homeland, indicating that he was not loyal to the Iron Throne and its new ruler, Joffrey.