Answer: sack Constantinople, the center of Byzantine Christianity and the largest Christian city.
Explanation:
As mentioned, the Crusaders had been promised money and aid on their way to retake Jerusalem from Muslims.
Emperor Alexius III was however dethroned before he could pay them and the situation in Constantinople, the capital of the Byzantine Empire and the largest city in Christiandorm, became so volatile that the Crusaders looted the city to reclaim the debt.
This single action so weakened the empire that when it was restored almost 60 years later, it was never the same as it was and so was easily defeated by the Ottomans when they attacked two centuries later.
In trade, barter (derived from baretor) is a system of exchange where participants in a transaction directly exchange goods or services for other goods or services without using a medium of exchange, such as money.
