Pangaea was the last of the great continents. Wegener hypothesized that all of the continents were one continent based on physical evidence that he collected. The shapes of the shores, matching mountain ranges and fossils/plants found on different continents. What Wegener did not have was the mechanism. Hess in 1963 discovered what is now called Mid-Ocean ridges. What accurs here is faults in the crust allow magma to move to the surface. The build up of magma, rift valeys leads to divergence of the plates moving apart. The continents began to pull apart and move away from each other. But as contnients move away from each other essentially they are also moving towards each other from another reference point. Now new have oceanic crust/plates moving towards continental plates leading to convergence. Look up the Wilson Cycle. It is like talking about what comes first, the chicken or the egg and if you do not look at the very beginning of earth it does not fully make sense.