Franz Xaver Sussmayr -LRB- German : Sußmayr ; sometimes written in English as Suessmayr ; 1766 -- September 17 , 1803 -RRB- was an Austrian composer , now famous for his completion of Wolfgang Amadeus Mozart 's Requiem .
His father was a sacristan and teacher .
His father was a sacristan and teacher .
Simplify this sentence: Franz Xaver Sussmayr -LRB- German : Sußmayr ; sometimes written in English as Suessmayr ; 1766 -- September 17 , 1803 -RRB- was an Austrian composer , now famous for his completion of Wolfgang Amadeus Mozart 's Requiem . Output: