Philadelphia is the largest city in Pennsylvania and the sixth-most-populous city in the United States.
In 2008, the population of the city proper was estimated to be over 1.4 million, while the Greater Philadelphia metropolitan area's population of 5.8 million made it the country's fifth-largest. The city is the nation's fourth-largest urban area by population and its fourth-largest consumer media market as ranked by the Nielsen Media Research. It is the county seat of Philadelphia County (with which it is coterminous). Popular nicknames for Philadelphia include Philly and The City of Brotherly Love .
A commercial, educational, and cultural center, the city was once the second-largest in the British Empire, and the social and geographical center of the original 13 American colonies. Ben Franklin took a large role in Philadelphia's early rise to prominence. It was in this city that many of the ideas, and subsequent actions, gave birth to the American Revolution and American Independence, making Philadelphia a centerpiece of early American history. It was the most populous city of the young United States, and served as one of the nation's many capitals during the Revolutionary War and after. Following the ratification of the U.S. Constitution, it was the temporary national capital from 1790 to 1800 while Washington, DC was under construction.
Prior to the arrival of Europeans, the Philadelphia area was the location of the Lenape (Delaware) Indian village Shackamaxon.
Europeans arrived in the Delaware Valley in the early 1600s, with the first settlements founded by the Dutch, British and Swedish. After Sweden's first expedition to North America embarked in late 1637, the Swedes took control of land on the west side of the Delaware River from just below the Schuylkill River: today's Philadelphia, southeast Pennsylvania, Delaware, and Maryland. In 1644, New Sweden supported the Susquehannocks in their military defeat of the English province of Maryland. But 11 years later, the Dutch sent an army to the Delaware River, nominally taking control of the colony, though Swedish and Finnish settlers continued to have their own militia, religion, court, and lands. The English conquered the New Netherland colony in October 1663–1664, but the situation did not really change until 1682, when the area was included in William Penn's charter for Pennsylvania.
In 1681, in partial repayment of a debt, Charles II of England granted William Penn a charter for what would become the Pennsylvania colony. Despite the royal charter, Penn bought the land from the local Lenape to be on good terms with the Native Americans and ensure peace for his colony. According to legend Penn made a treaty of friendship with Lenape chief Tammany under an elm tree at Shackamaxon, in what is now the city's Fishtown section. As a Quaker, Penn had experienced religious persecution and wanted his colony to be a place where anyone could worship freely despite their religion. Penn named the city Philadelphia, which is Greek for brotherly love (philos, "love" or "friendship", and adelphos, "brother"). Penn planned a city on the Delaware River to serve as a port and place for government. Hoping that Philadelphia would become more like an English rural town instead of a city, Penn laid out roads on a grid plan to keep houses and businesses spread far apart, allowing them to be surrounded by gardens and orchards. The city's inhabitants didn't follow Penn's plans and crowded by the Delaware River and subdivided and resold their lots. Before Penn left Philadelphia for the last time, he issued the Charter of 1701 establishing Philadelphia as a city. The city soon established itself as an important trading center, poor at first, but with tolerable living conditions by the 1750s. Benjamin Franklin, a leading citizen of the time, helped improve city services and founded new ones, such as the American Colonies' first hospital.
Philadelphia's importance and central location in the colonies made it a natural center for America's revolutionaries. The city hosted the First Continental Congress before the war; the Second Continental Congress, which signed the United States Declaration of Independence, during the war; and the Constitutional Convention after the war. Several battles were fought in and near Philadelphia as well. After the war, Philadelphia served as the new United States' capital in the 1790s. In 1793, the largest yellow fever epidemic in U.S. history killed as many as 5,000 people in Philadelphia, roughly 10% of the population.
The state government left Philadelphia in 1799 and the federal government left soon after in 1800, but the city remained the young nation's largest and a financial and cultural center. New York City soon surpassed Philadelphia in population, but construction of roads, canals, and railroads helped turn Philadelphia into the United States' first major industrial city. Throughout the 19th century, Philadelphia had a variety of industries and businesses, the largest being textiles. Major corporations in the 19th and early 20th centuries included the Baldwin Locomotive Works, William Cramp and Sons Ship and Engine Building Company, and the Pennsylvania Railroad. Industry, along with the U.S. Centennial, was celebrated in 1876 with the Centennial Exposition, the first official World's Fair in the United States. Immigrants, mostly German and Irish, settled in Philadelphia and the surrounding districts. The rise in population of the surrounding districts helped lead to the Act of Consolidation of 1854 which extended the city of Philadelphia to include all of Philadelphia County. In the later half of the century immigrants from Russia, Eastern Europe and Italy and African Americans from the southern U.S. settled in the city.
By the 20th century, Philadelphia had become known as "corrupt and contented," with a complacent population and entrenched Republican political machine. The first major reform came in 1917 when outrage over the election-year murder of a police officer led to the shrinking of the Philadelphia City Council from two houses to just one. In the 1920s, the public flouting of Prohibition laws, mob violence, and police involvement in illegal activities led to the appointment of Brigadier General Smedley Butler of the U.S. Marine Corps as director of public safety, but political pressure prevented any long-term success in fighting crime and corruption.
The population peaked at more than two million residents in 1950, then began to decline while its suburban counties grew. Revitalization and gentrification of neighborhoods began in the 1960s and continues into the 21st century, with much of the development in the Center City and University City areas of the city. After many of the old manufacturers and businesses had left Philadelphia or shut down, the city started attracting service businesses and began to more aggressively market itself as a tourist destination. Glass-and-granite skyscrapers were built in Center City.