According to the Internet source given below, Johann Pfeiffer was born in Nuremberg and had his earliest music lessons with various teachers in his home town. After studying law in Leipzig and Halle he worked for six months in the Hofkapelle of the count Heinrich Reuß-Schleiz. From 1720, he was employed as a violinist in the Hofkapelle (Court Orchestra) in Weimar. In 1726 he became concert master there and Duke Ernst August gifted him a valuable violin made by Jakob Stainer. In the years 1729 and 1730 he accompanied his employer on a trip through Holland, the Hapsburg Netherlands and France. In 1732 Pfeiffer spent several in months Berlin, before he became the Hofkapellmeister of Margrave Friedrich III in Bayreuth on the recommendation of the Crown Prince, Friedrich II. In Bayreuth he also gave lessons to Wilhelmine of Prussia in composition, violin playing, and continuo and also joined the Masonic Lodge Zur Sonne.
After the death of Wilhelmine in 1758, the court orchestra was reduced and Pfeiffer was released from his position as concert master, although he remained connected to the court in Bayreuth as a well respected violinist and composer until his death in 1761.

Websites:
	Johann Pfeiffer	Biography by wikipedia.org.