Complex sentence: During Florida's Second Spanish Period, it was the site of Fort San Nicolas, which guarded the river crossing at the Cowford, which led to the area between the ferry and Miller's Creek being known as "San Nicolas".
Split into simpler sentences: During Florida's Second Spanish Period, it was the site of Fort San Nicolas, which guarded the river crossing at the Cowford. This led to the area between the ferry and Miller's Creek being known as "San Nicolas".