What is the difference between a forefather and an ancestor?

Stumbled upon this question today while going through synonyms of various terms. I was advised that they are not synonymous to each other.

Please advise.

"Ancestors" has only one meaning. Your ancestors are your relatives several generations back who lived, and, it is commonly understood, had already died, by the time you were born.

"My ancestors arrived in Australia from Ireland in the 1790s."

"Hominids are our human ancestors."

English-speakers sometimes use "forefather" as a synonym for "ancestor."

"Our forefathers passed these customs down to us."

But it also has a more fanciful meaning, often referring to the originator of an idea or tradition, or a person who established an important precedent in some sort of field, like "forerunner."

"Alan Turing is the forefather of modern computing."