It always seems that women who have curly hair want straight hair, and those who want straight hair will go to great lengths to have curls. In fact, women have been trying ways to change the wave patterns in their hair for centuries. Using heat to curl or straighten hair, known as thermal styling, has been around since 1875. That year, Marcel Grateau invented a system of heated rollers to create waves in straight hair. This is still called “Marcelling” or Marcel Waving by many professional stylists.