Legend says that shortly after William Penn arrived in the new province of Pennsylvania in 1682, he met a group of Native Americans, the Lenni Lenape, in an area on the Delaware River under an elm tree. This area, known as Shackamaxon, was neutral ground among the tribes, a place where they would fish, hunt, and fashion treaties among themselves. There they formed a Treaty of Friendship with Penn, and the elm became a symbol for this peaceful event.
The "Great Elm," as it was known, was immortalized by artists such as Thomas Birch and Benjamin West, and stood on the banks of the Delaware for more than 120 years. In March 1810, the tree was brought down during a large storm, but it was not forgotten.
Objects were created from the wood, including a box that was made for Chief Justice John Marshall in 1831. Marshall said: "The box is to me an inestimable relique. I know no inanimate object more entitled to our reverence than the tree of which it was a part, because I think few events in history have stronger claims on our serious reflection, on our humanity, our sense of rights, and on our judgment, than the treaty which was made under it, and the consequences which followed that treaty."
In the tree's place, an obelisk was erected in 1827. Today, in Penn Treaty Park, just north of Penn's Landing, a monument to the commonwealth's founder recalls the event and the tree.