First the USA Historical Perspective
 
The following states are the first 13 states to ratify the United State of America constitutional government:
 
Delaware was the first to ratify the constituion government in December 1787 along with PA and New Jersey. Georgia and Connecticut followed in January 1788. Six more states followed later in 1788: Mass, MD, Virginia, New York, New Hampshire, S Carolina.  In 1789 N Carolina signed and in 1790 Rhode Island signed.
 
The 1999 Pennsylvania State Quarter is the second coin in the U.S. Mint's 50 State Quarters Program, released on March 8, 1999.  
 
It features the "Commonwealth" statue atop the Pennsylvania State Capitol dome on the reverse. Her right arm is extended in mercy; her left arm holds a ribbon mace to symbolize justice. 
 
The design also includes an outline of the state and a keystone. During the Civil War, Pennsylvania earned its nickname as the “Keystone State.” Its location was seen as “key” in the wall against attack from the south. The Battle of Gettysburg, a critical turning point in the war, took place in the southeast corner of Pennsylvania. 
 
 The obverse displays the standard Washington Quarter design with inscriptions "United States of America," "Liberty," "In God We Trust," and "Quarter dollar".
 
This coin is a 1999P Pennsylvania State Quarter of a Double Die Reverse errors variety. This coin is made of nickel clad copper and bears the face value of 25 cents. It is uncirculated and ungraded, minted in Philadelphia, United States. As a collector's item, this unique State Quarter offers a rare opportunity to own a piece of history with its specific variety and characteristics.
 
Notes:  First 13 United States
Delaware: December 7, 1787
Pennsylvania: December 12, 1787
New Jersey: December 18, 1787
Georgia: January 2, 1788
Connecticut: January 9, 1788
Massachusetts: February 6, 1788
Maryland: April 28, 1788
South Carolina: May 23, 1788
New Hampshire: June 21, 1788 (With this state’s ratification, the Constitution became legal.)
Virginia: June 25, 1788
New York: July 26, 1788
North Carolina: November 21, 1789
Rhode Island: May 29, 1790 (Rhode Island did not hold a Constitutional Convention.)