That’s a substantial amount of gold.

One of the most ironic moments in the entire series occurs early on, when Harry discovers the vast sum of gold his parents have left for him. He grew up in a less-than-affluent household, essentially living under the stairs as a servant.
He was obviously ecstatic when he discovered all of the money he had inherited. Where did the money come from, though? It was obviously his parents’, but how did they amass so much wealth? Were there any other relatives to whom it should have been given? Questions, questions, questions.