The Standoff at the Great Sept of Baelor is an unsuccessful attempt by House Tyrell and House Lannister to crack down on the Faith Militant. The plan was meant to force the release of Margaery Tyrell from imprisonment with the threat of military force. Although the army of House Tyrell is significantly stronger than the Faith Militant, the assault was called off when King Tommen Baratheon supported the Faith. This was a significant blow to the then two most powerful houses in Westeros.