What was the name of the 1968 head-mounted display created by Ivan Sutherland and Bob Sproull?

The 1968 head-mounted display created by Ivan Sutherland and Bob Sproull was called the Sword of Damocles.

Built at Harvard University, the system is widely regarded as the first virtual-reality and augmented-reality head-mounted display. It was suspended from the ceiling because its computer hardware and mechanical tracking apparatus were too heavy for a user to wear safely.

The display showed simple wire-frame computer graphics that changed perspective as the user moved their head. This introduced a key VR principle: the rendered view should respond to the user’s position and orientation.

The name came from the device’s threatening appearance as it hung above the wearer. It is sometimes described only as an early VR headset, but its ability to overlay computer graphics on the real world also makes it an important ancestor of augmented-reality systems.