Original: In 1638, Galileo published his analysis of several situations—including the celebrated "interrupted pendulum"—which can be described (in modern language) as conservatively converting potential energy to kinetic energy and back again.
Simplified: In 1638, Galileo published his analysis of several situations -- including the celebrated "interrupted pendulum" -- which can be described (in modernized language) as conservatively converting potential energy to kinetic energy and back again.