In 1859 the Irish mathematician Sir William Rowan Hamilt onpropose daga mein which it was required to find a dodeca hedron bypass around its edges with a return to the starting point. In his honor, the corresponding path in the graph was later called the Hamiltonian cycle: it is the spanning cycle in the graph, that is, the cycle passing through all the vertices of the graph. A graph containing a Hamiltonian cycle is said to be Hamiltonian.
