How did Emperor Diocletian affect the course of Roman history?

He divided the empire into two halves and shared his power with a co-emperor.
He was the first emperor to retire from office, setting a precedent for future rulers.
He established fixed prices for goods and services to halt inflation.
He announced that all noblemen would use the title dominus, which means "master."

Question

How did Emperor Diocletian affect the course of Roman history?  
  
 He divided the empire into two halves and shared his power with a co-emperor. 
 He was the first emperor to retire from office, setting a precedent for future rulers. 
 He established fixed prices for goods and services to halt inflation. 
 He announced that all noblemen would use the title dominus, which means "master."

anonymous · Answer

he divided the empire into two halves and shared his power with a co-emperor.