why was the happy unhappy?

The Happy Prince is the statue of a deceased prince who had lived his entire life without knowing sorrow. The ornate statue is stunning and is encrusted with sapphires, a ruby, and gold leaf. In death, the Happy Prince despairs of the suffering of his people, which compels him to ask the Swallow to donate all the gems he possesses. In the end, he is left completely bare and the Mayor orders him pulled down, but he and the Swallow are united in heaven with God.