http://www.quora.com...r-get-grayscale
A Dance With Dragons, page 577:
"Prince Aerys...as a youth, he was taken with a certain lady of Casterly Rock, a cousin of Tywin Lannister. When she and Tywin wed, your father drank too much wine at the wedding feast and was heard to say that it was a great pity that the lord's right to the first night had been abolished. A drunken jape, no more, but Tywin Lannister was not a man to forget such words, or the...the liberties your father took during the bedding."