Hamiltonian path
Hamiltonian paths  and cycles and cycle paths are named after William Rowan Hamilton who invented the Icosian game. This game is also known as Hamilton's puzzle. It involves finding a Hamiltonian cycle in the edge graph of the dodecahedron.  Hamilton solved this problem using the Icosian Calculus, an algebraic structure based on roots of unity with many similarities to the quaternions (also invented by Hamilton).  This solution does not generalize to arbitrary graphs. However, despite being named after Hamilton, Hamiltonian cycles in polyhedra had also been studied a year earlier by Thomas Kirkman.