 In 1659 van Heuraet published a construction showing that the problem of determining arc length could be transformed into the problem of determining the area under a curve (i.e., an integral).As an example of his method, he determined the arc length of a semicubical parabola, which required finding the area under a parabola.In 1660, Fermat published a more general theory containing the same result in his "De linearum curvarum cum lineis rectis comparatione dissertatio geometrica" (Geometric dissertation on curved lines in comparison with straight lines).