Actually, radio control preceded control line - or at least the form we know today (sometimes called U Control or "ukie" for short). So the order is free flight, radio control and finally control line.

In 1942, Jim Walker from the Portland, Oregon area devised a control mechanism consisting of a handle the pilot grips, two lines connected to a bellcrank mounted in the model. Sometimes a 3rd line is used for throttle control. If you like the feeling of being directly connected to your model and can feel every bit of feedback caused by speed, wind, attitude, power, etc, control line flying is an exciting form of model aviation.

http://www.americanjuniorclassics.co...trolpatent.htm