The Gantt Chart was invented by Henry Laurence Gantt during the 1910's. He passed away in 1919, but in the 1920's, his charts started becoming an accepted visual aid for the progression and tracking of a project. By the 1950's, his charts were being used in many major projects all over world.
The first Gantt Charts were nothing more than a series of tasks on the left hand side of the paper, with a calendar of dates running across the top. All you had to do was color in a bar to represent the length of time each task was to take, and therefore you were able to see an estimate of how long the entire project should take. Looking at this, you could also see the progress on a project, the same way you can with today's Gantt Charts.
Milestone Charts were also used in conjunction with this basic Gantt Chart, to notate only the important portions of a project. In today's project management and Gantt Charts, we generally see the two charts combined, so that we can see the timeline and milestone expectations together.