Amsterdam
The city was one of the first cities in Western Europe to be fairly democratic: Wealthy citizens chose the leaders of the city. Amsterdam declared war on the Spanish in 1578, during the Eighty Years' War. When the city of Antwerp fell to the Spanish in 1585, many people of Antwerp fled to Amsterdam. Antwerp was also a major trading city, and when its people moved to Amsterdam, they took their trading-networks with them. That's why Amsterdam became an even more important trading city after that. This launched the Dutch Golden Age. The number of people living in Amsterdam during the War rose from less than 30,000 in 1570 to over 100,000 in 1622. That number would even rise to 200,000 near the end of the 17th century, making the city a very large city for its time (only London and Paris also had that many people). In the 18th century, the number of people living in Amsterdam fell back to 140,000, ending the Golden Age.