War between 1618 and 1648 devastated Berlin. One third of its houses were damaged or destroyed, and the city lost half of its population. Frederick William, known as the "Great Elector", who had succeeded his father George William as ruler in 1640, initiated a policy of promoting immigration and religious tolerance. With the Edict of Potsdam in 1685, Frederick William offered asylum to the French Huguenots. More than 15,000 Huguenots went to Brandenburg, of whom 6,000 settled in Berlin. By 1700, approximately 20 percent of Berlin's residents were French, and their cultural influence on the city was immense. Many other immigrants came from Bohemia, Poland, and Salzburg.
With the coronation of Frederick I in 1701 as king (in K�nigsberg), Berlin became the new capital of the Kingdom of Prussia (instead of K�nigsberg); this was a successful attempt to centralize the capital in the very outspread Prussian Kingdom, and it was the first time the city began to grow. In 1740, Frederick II, known as Frederick the Great (1740�1786), came to power. Under the rule of Frederick II Berlin became a center of the Enlightenment. Following France's victory in the War of the Fourth Coalition, Napoleon Bonaparte marched into Berlin in 1806, but granted self-government to the city. In 1815 the city became part of the new Province of Brandenburg.
The Industrial Revolution transformed Berlin during the 19th century; the city's economy and population expanded dramatically, and it became the main rail hub and economic center of Germany. Additional suburbs soon developed and increased the area and population of Berlin. In 1861, outlying suburbs including Wedding, Moabit, and several others were incorporated into Berlin. In 1871, Berlin became capital of the newly founded German Empire. On 1 April 1881 it became a city district separate from Brandenburg.
At the end of World War I in 1918, a republic was proclaimed in Berlin. In 1920, the Greater Berlin Act incorporated
