In mathematics, a Hamiltonian path in a graph is a path that visits each vertex precisely once. A Hamiltonian cycle is a cycle which visits each vertex once and only once.
This type of path is named after William Rowan Hamilton who invented a puzzle, now known as Hamilton's puzzle, about the construction of such paths.
... February 25, 1500-San Jerónimo de Yuste[?], Spain September 21, 1558) was Holy Roman Emperor (as Charles V) from 1519-1558; he was also King of Spain from 1516-1556 -- ...