How has the concept of happiness changed over history?

Actually there is some truth to your claim. The ancient Greek word eudaimonia is sometimes translated as "happiness," but a better translation IMO is probably something like "living well." The problem with the term happiness in the contemporary context is that it might refer to a non-permanent, fleeting condition, or subjective psychological state-of-affairs, whereas ancient Greek discussions of eudaimonia typically focus on a more permanent state, something like what we might refer to as a process of "self-actualization" or "flourishing." According to Aristototle, eudaimonia is certainly something we ought to strive for (by practicing virtuous action via an enduring process of habituation), but it is not something we can accomplish all by ourselves. In other words, for Aristotle, virtuousness is a necessary but not sufficient condition for the achievement of happiness / eudaimonia. Other things are required, such as friends, wealth, honour, etc. He even went so far as to claim that extreme ugliness might preclude one from living the kind of flourishing life that his project sets out to describe. Commentators on Aristotle usually refer to these kinds of valuable things as "external goods." So, on Aristotle's account, while happiness / eudaimonia is not something totally beyond our control, (contra the Stoics and other Ancient Greek and Roman thinkers), it is also not something that flows purely from the exercise of the human will alone. I hope this makes some sense. Source: Aristotle, Nicomachean Ethics (Indianapolis: Hackett, 1986).
Edit: one missing word.