In 229, Sun Quan declared himself "Emperor of Wu". His attacks on Wei were all in vain but he managed to develop his country very well. After his son Crown Prince Sun Deng died in 241, he made his now-oldest son Sun He Crown Prince. All along the next nine years, He would have trouble with his brother Sun Ba who wanted to be Crown Prince instead. Their fight even caused the honorable general Lu Xun to die of anger in 245.