The Seismic Pieces of Eden were Isu artifacts stored within at least three different Seismic Temples spread across the world. Described as "Trees" and "Roots" by Shay Cormac, in comparison to the "Apples", these Pieces of Eden served as a stabilising measure for their Temples, and the region in which they resided; once disturbed, the Pieces would disintegrate and the surrounding area almost instantly destabilized, causing an earthquake.
In 1751, François Mackandal, Mentor of the Haitian Assassins, discovered the location of a Seismic Temple in Port-au-Prince by using both the Precursor box and manuscript, and sent Vendredi to obtain any Piece of Eden he might find there. Vendredi's efforts disturbed the Piece of Eden, leading to an earthquake that destroyed the city.
By 1754, both the Precursor box and manuscript were in the possession of the Colonial Assassins, who were able to pinpoint another Temple's location in Lisbon, Portugal. Their Mentor, Achilles Davenport, sent Shay Cormac to retrieve the Temple's Piece of Eden in November 1755, assuming it to be an Apple. Shay also disturbed the Piece of Eden, causing another earthquake that destroyed the city of Lisbon and killed thousands of citizens.
At least one more of these artifacts remained, in a remote Temple in the Arctic. In 1760, Achilles and Liam O'Brien travelled to the Temple to retrieve the Piece of Eden, with Templar Grand Master Haytham Kenway and Shay Cormac in pursuit to stop their endeavour. During the altercation that followed, Liam accidentally removed the Piece of Eden from its pedestal, triggering another earthquake. Unlike the previous earthquakes, there were no reported causalities, due to the Temple's remote location.