Pyke is one of the Iron Islands, an archipelago located on Ironman's Bay, on the western side of Westeros. The island is the site of the castle of the same name, which serves as the seat of House Greyjoy, the ruling house of the Iron Islands, and the town of Lordsport.
During Greyjoy Rebellion, Pyke island is the site of the Siege of Pyke, which ends with the defeat of House Greyjoy at the hands of the combined armies of King Robert Baratheon and Lord Eddard Stark. As a result, the Ironborn King Balon Greyjoy submits to the Iron Throne and surrenders his last remaining son and heir Theon Greyjoy to Ned Stark's custody. During the siege, several of the towers at Pyke castle were pulled down.
The King in the North Robb Stark sends Theon to Pyke to negotiate an alliance against the Iron Throne with Lord Balon. Since Pyke lacks a harbor, Theon's ship lands in the town of Lordsport. There, he is picked up by his older sister Yara Greyjoy, whom he does not recognize. Yara and Theon travel on horseback to Pyke castle where a tense family reunion occurs. Balon rejects Robb's offer of an alliance and reveals that he has other plans.
Pyke castle latest hosts Balon's war council where he outlines his plan to conquer the North. Following a tense discussion, Theon chooses his birth family and renounces his allegiance to Robb Stark. As an affirmation of his new loyalty, Theon is baptized by a Drowned Men priest in the presence of his father and sister. Having committed himself to the Ironborn cause, Theon is given command of the Ironborn crew of the Sea Bitch. While docking in the harbor, Theon has trouble winning the respect of the unruly crew but finds an ally in the form of his first mate Dagmer Cleftjaw.
On Pyke, A mounted messenger delivers a scroll and box from Ramsay Snow to Lord Balon. Ramsay is the illegitimate son of Roose Bolton, the new Warden of the North. Balon and Yara receive the scroll and box and learn that Ramsay has captured and emasculated Theon. Ramsay threatens to mutilate Theon further and to kill every Ironborn in the North if Balon does not end his invasion. Unwilling to yield his gains, Balon rejects Ramsay's terms and disowns his son. Yara disagrees and mounts a rescue mission to bring back Theon.
At Pyke Castle, Balon and Yara receive news that the Glovers have recaptured Deepwood Motte in the North. The loss of the last major stronghold in the North deals a serious blow to Balon's military campaign. However, he refuses to accept defeat and chastises his daughter for criticizing his strategy. Later that night, Balon encounters his estranged younger brother Euron Greyjoy on a rope bridge. Euron expresses his desire to take the Salt Throne and following a struggle, throws Balon to his death in the sea below. The following day, Balon's body is recovered from the sea by Yara and her uncle Aeron Greyjoy. Following a brief funeral, they bury the former King in the sea.
In the books
In the A Song of Ice and Fire novels, the island of Pyke serves as home to both House Greyjoy and House Botley, which holds Lordsport.
According to The World of Ice and Fire (2014), officially, no one is sure if the island is named after the castle or the other way around. The Greyjoys claim that the island is named after their Pyke castle (after they came to dominate the rest of the island), while the smallfolk of the island say that it was always called "Pyke", and the castle is named after the island.
The four largest of the Iron Islands - Great Wyk, Harlaw, Orkmont, and Pyke - have mines which rich supplies of iron, lead, and tin. Pyke isn't as wealthy as Harlaw and Great Wyk, however, or even Orkmont: instead the Greyjoys were selected to rule all of the islands after the Targaryen Conquest due to their distinguished lineage stretching back to the Dawn Age, and the great respect they already commanded from the other ironborn.
Over time their rule did enrich Pyke island (probably through various shipping benfits, etc.) so that the largest town in the Iron Islands is Lordsport, also on Pyke island (ruled by House Botley). Even Lordsport, however, is modestly sized compared to larger trading towns on the mailand.
The events on Pyke including the assassination of Balon Greyjoy and Euron's takeover are only mentioned in passing in the novels A Storm of Swords and A Feast for Crows. By contrast, Season Six shows Balon's death onscreen and identifies Euron as the culprit. Unlike the novels, Yara (called Asha in the books) is present when Balon's body is recovered from the sea and subsequently attends his funeral with Balon's youngest brother Aeron Greyjoy, a Drowned Men priest.