The lever and its properties were already well known before the time of Archimedes, and he was not the first to provide an analysis of the principle of the lever.[5] The earlier Mechanical Problems, once attributed to Aristotle but most likely written by one of his successors, contains a loose proof of the law without employing the concept of centre of gravity. There is another short work attributed to Euclid entitled On the Balance that also contains a mathematical proof of the law of the lever, again without recourse to the centre of gravity.[6]