There are various synonyms for the phrase "following upon," which means the act of coming after or as a result of something. One can use the term "ensuing" to describe something that comes after an event or action. Another word to use is "succeeding," which refers to a situation where one thing replaces another. Additionally, "subsequent" is an appropriate synonym to use as it implies a relationship between two events in time. Other synonyms for "following upon" include "ensuing," "resulting," and "proceeding." These words give writers more options to choose from when trying to describe the sequence of events.