Lord Petyr Baelish’s great-grandfather was a Braavosi sellsword in the service of Lord Corbray, so when his son became a hedge knight he took the stone head of the Titan of Braavos as his sigil. Lord Baelish’s father was the smallest of small lords of a few rocky acres on the smallest of the Fingers. Lord Petyr has greatly advanced his house, winning a place as a tax collector for the crown ten years ago and swiftly rising to a place on the king’s small council as Master of Coin.
Previously, Lord Petyr had been fostered at Riverrun with Lord Tully’s son (who first named him Littlefinger) and daughters but, at the age of fifteen, was cast out after challenging Brandon Stark for Catelyn Tully’s hand and losing.
After lying to the Starks concerning an attempted killing of their crippled son, Bran, Littlefinger eventually betrayed Lord Eddard after Robert’s death by buying the City Watch on behalf of Queen Cersei rather than the Hand. For this service and his later aid in preparing the Lannister-Tyrell alliance, Lord Petyr has been named Lord Paramount of the Trident and Lord of Harrenhal before being dispatched to marry Lysa Arryn. Shortly after, King Joffrey was poisoned at his wedding feast and it was revealed to be a plot concieved and carried out by Littlefinger and Olenna Tyrell (and possibly young Queen Margaery as well). It was done in such a way that Sansa Stark fled to him (Dontos Hollard, her confidant, was in fact working with Littlefinger and was murdered by him when he delivered Sansa to him) and Tyrion Lannister was blamed.
On arriving in the Vale at last, he married Lady Lysa Arryn (whose husband she had poisoned with his aid), whom he had already had a relationship with both at Riverrun and King’s Landing. Afterwards, he was named Lord Protector of the Vale. Not long after, he murdered her in front of Sansa Stark (whom he called Alayne Stone, his bastard daughter) and placed the blame on Marillion, Lysa’s favorite singer.