The first biography of Siddhartha, the future Buddha, reveals that for a long time he was entirely unaware of the wretchedness of the human condition. A royal son, he spent his youth in pleasure and luxury, surrounded by music and worldly delights. He was already married by the time the gods decided to enlighten him. One day he saw a decrepit old man; then the suffering of a very sick man; then a corpse. It was only then that the existence of old age, suffering, and death—all the painful aspects of life to which he had been oblivious—was brought home to him. Upon seeing them he decided to withdraw from the world to become a monk and seek the path to Nirvana.
We may suppose, then, that he was happy as long as the grim realities of life were unknown to him; and that at the end of his life, after a long and arduous journey, he attained the genuine happiness that lies beyond the earthly condition.