Even before Christ, there existed wonderful philosophy in Greece and Rome. The ancient Romans were practical people. They did not ask themselves theoretical questions. They asked how they, as people, could become happy. They concluded that they must keep the source of happiness within themselves. They were the Stoic Philosophers. The writers included Epictetus and the Emperor Marcus Aurelius. They were wise and wonderful.
The Stoics believed that they could not depend on the "outside" for happiness. The "outside is beyond my control. I must keep some control over my happiness or I will always be a victim. Example: I would be happy if my wife (or husband) were cheerful in the morning. I will be happy when I win the lottery. This is not the road to happiness. Happiness is securely found only from within.
The Stoics said that we could not let our desires go unrestrained. If I let my desires go wild, I can convince myself that I need a yacht to be happy. I do not need a yacht, or a DVR or a Porsche, or a widescreen TV. We can decide what we need; we can be content with what we have. In this regard, there are two ways to get rich. I define a rich person as one who earns more than s/he wants to spend. You could earn a fortune, more than you could ever want to spend. Or you could limit your desire to spend. J.P. Morgan chose the first way. Francis of Assisi chose the second. They were both rich.
The Stoics were a secular philosophy. They did not bring God into the picture. When we take the Stoic wisdom and add our spirituality, then we really have a plan of life. Look inside yourself for happiness. Inside you find the God who loves you. This God is the only sure source of happiness. Now we find that Francis of Assisi just might have been the happiest individual whoever lived.