This other term for a pastor is derived from the Middle Latin word persona
Derived Forms ... Word Origin and History for par
son [DOC] [TLE] Minister | Define Minister at Dictionary.com [PAR] Minister definition, a person authorized to conduct religious worship; member ... 
Middle English ministre, minister (< Old French ministre) < Latin minister servant,
... [DOC] [TLE] Literary Terms and Definitions P - Carson-Newman College [PAR] It was a very common practice in medieval times since paper was so expensive.