Many of the occupants of the Judengasse were involved in moneylending and moneychanging.
Originally the Jews were active in domestic and international trade.
However, from the 12th century they were forced out of this field by Christian competitors and limited to moneylending.
There were also theological reasons for this development.
The teaching of the Christian church forbade Christians to charge interest, and lending at interest was accordingly officially limited to the Jews.
This created a highly contradictory situation.
On the one hand lenders had become economically indispensable, on the other hand the lenders (the Jews) were condemned.
This was a very important basis for the church's antisemitism.
However, church teaching did not prevent the growth of Christian moneylending.
The great financial capitalists at the dawn of the modern era were the Fuggers, Welsers and Imhofs, all Christian.
In addition the Jews had again expanded beyond moneylending, which included particularly pawnbroking, and were active in various forms of trade.
They continued to play a major role as moneychangers and moneylenders and in the 17th and 18th centuries as court factors.
During the 18th century these activities evolved into banking as we know it today.
Thanks to the experience the Jews had accumulated over generations in moneylending, they were particularly active in banking in the 19th century.
The name of Rothschild in particular became symbolic of the importance of the Jews in banking.
Although the Jews played an important role in moneylending and banking over the centuries, their actual influence was frequently overestimated by Christians.
This overestimate was often an expression of strong antisemitic feelings.