Well, aristocracy in up to recent (ie pre 20th century) times was tied to land-owning, for various reasons (likely most importantly the titles which came with military service/obligation as well). Obviously this would differ from state to state, eg the Byz Empire was not feudal but more of a byzantine web of families stabbing each other, and people could rise to power in different ways too, which is why there were so many dynasties and one-offs.
But Oligarchy was historically borne out of trade, cause the Aristocracy was of a noble line, whereas the oligarchy were people without titles who came to make loads of money and so fought for power as well. The setting of the birth of such distinctions are the Greek politiae of old, where usually aristocracy was changed with oligarchy, and democracy. (tyranny, btw, had a very different meaning than now, and signifies etymologically just that someone usurped power, ie did not come to have it through lawful mean. So a benevolent tyranny was very much possible).
