forerunner
1. [ noun ] a person who goes before or announces the coming of another
Synonyms: precursor
Related terms: person predecessor
2. [ noun ] an indication of the approach of something or someone
Synonyms: herald precursor harbinger
Related terms: indication announce
3. [ noun ] anything that precedes something similar in time
Synonyms: antecedent
Examples:

"phrenology was an antecedent of modern neuroscience"

Related terms: temporal_relation