If you’re historically inclined, you may be interested to know that the first swept-wing airplane appeared in 1907. It was built by J. W. Dunne, a gifted Irishman who also had some interesting ideas about the nature of Time. It had the distinction of being stable in all axes — uncapsizeable, in the boat-influenced language of the era. Wing sweep played a part in its stability; it provided a powerful dihedral effect, tending to roll the airplane out of a sideslip and consequently to keep it right side up without pilot attention, like a model glider.
Like many aspects of wing shape that designers tried out during the first two or three decades of powered flight, marked sweep — the Dunne biplanes had about 30 degrees — was eventually discarded. By World War II, the “ideal” wing shape was straight, moderately tapered, with an aspect ratio of between five and nine, and rounded tips.
