"Follow upon" is a phrase used to indicate something that comes after or pursues something else. There are several synonyms for this phrase that can be used interchangeably. "Succeed", "ensue", "result", "occur", "happen", "come after", and "follow up" are some of the synonyms that can be used instead of "follow upon". These words can be used in various contexts and imply that something is happening as a consequence of another event. Whether it be a chain of events or a reaction to something, there are many ways to express the notion of something following upon another occurrence.