appearedDuringReignOf

Given a predicate that represents a relationship or action between entities, generate a one-sentence description explaining its meaning.  
# Instructions
Focus on describing the relationship, not the entities themselves. 
# Response Format
Begin the description with \' Indicates...\'

Predicate: appearedDuringReignOf

Indicates that one entity came into existence, became active, or was first observed while another entity (typically a ruler or regime) was in power.