The flag of the Commonwealth of Pennsylvania consists of a blue field on which the state coat of arms is embroidered. Originally authorized by the state in 1799, the current design was enacted by law in 1907. The blue field must, by legislative mandate, match the shade of blue in the US flag (Pantone 282c).
The state coat of arms is surrounded by draft horses on both sides, and a bald eagle, which represents Pennsylvania's loyalty to the United States, above. The state coat of arms includes a ship under full sail, a plow, and three sheaves of wheat indicating the significance of commerce, labor, perseverance and agriculture to the state. Surrounding the coat of arms is a stalk of Indian corn on the left and an olive branch on the right. These represent the state's recognition of its past and its hope for the future. The scroll below the coat of arms reads: "Virtue, Liberty and Independence," which is the state's motto.
In the summer of 2007, a bill was introduced to the state legislature to add "Pennsylvania" to the bottom of the flag in golden letters. The Pennsylvania House of Representatives voted in favor of the change. The legislation was proposed by State Representative Tim Solobay. The Senate has not yet taken action on the bill.
Pennsylvania received the nickname "The Keystone State" in reference to its importance in early American history. It was located in the center of the original thirteen states, between the North and the South. Many documents, like the United States Declaration of Independence, were signed in the state. The state was also an economical "keystone", concentrating both industry, like northern states, and agriculture, like southern states. The keystone currently appears in all kinds of official imagery, such as road signs, car license plates, the government website, logos of government departments, and the state quarter. It is central to many flag proposals as well. In some designs, it's substituted by keys.
William Penn was the founder of the Province of Pennsylvania, which became the current Commonwealth of Pennsylvania in 1783. During his government, the city of Philadelphia was planned and developed. Moreover, he was an early champion of democracy and religious freedom.
In his honor, Pennsylvania received the "Quaker State" nickname, in reference to Penn's belonging in the quaker movement.
Penn family's coat of arms can be blazoned as "argent, on a fess sable three plates", i.e., white with three white circles on a black horizontal stripe.