The design on the blue Pennsylvania flag dates back to the 1770s.  Then, in 1878, Caleb Lowes designed a new coat of arms with a shield, which is shown on the Pennsylvania PA flag.   The shield is divided into three sections, showing a ship, a plow and three sheaves of wheat.  The ship represents the ongoing world trade that Pennsylvania has engaged in.  The plow stands for farming, and the wheat, the abundant harvests, as well as wealth that comes form human thought and action.  On top is an eagle representing the United States and at the bottom, an olive branch and stalk of corn are crossed.  Two black horses wear harnesses, which are said to show that they are ready to draw the car of state out of all difficulties to the solid rock of prosperity. Pennsylvania State  Flag Adopted:  1907