Jacob Stainer is known as der Vater der deutschen Geige (the father of the German violin). Stainer's violins and violas were the most sought after in the world until the beginning of the 19th century. Stainer's instruments were the favored instruments of the Bach and mozart families. Stainer's instruments have very full arching and vertical f-holes.
The Stainer viola on display at the Metropolitan Museum of Art in New York was made at the height of Stainer's career and is rare example of a true tenor instrument with a large body and tall ribs -- most such instruments have been cut down in size over time as repertoire became more technically demanding.
Stainer's instruments remained the most sought after in the world until the beginning of the 19th century, when performers striving to be heard over loud orchestras and in large concert halls began to prefer the brighter sound and bigger projection of instruments by Antonio Stradivari.
Here are my photos of this viola: