The short version
The device most often called the first virtual reality headset was a head-mounted display built in the late 1960s by Ivan Sutherland, then at Harvard, with his student Bob Sproull. It is also called the Sword of Damocles, a nickname referring to the way it hung above the user’s head. Whether it was literally the first depends on definitions. It is better described as the first well-documented system that combined a head-worn display, head tracking and a computer that generated the images, which are the ingredients usually meant by the term.
Background: the ultimate display
In 1965 Sutherland wrote a short paper, often titled “The Ultimate Display,” imagining a room in which a computer controlled the existence of matter. It was a thought experiment more than a design, but it described a goal: a display so convincing that a viewer could treat it as a real space. A few years later, working first at Harvard and then with colleagues at the University of Utah, he turned part of that idea into hardware. Sutherland had already contributed to interactive computer graphics through his Sketchpad program in the early 1960s, so the project drew on existing expertise.
What the device was
The display used two small cathode ray tubes, one in front of each eye, with optics that made the images appear farther away. The computer drew simple wireframe shapes, such as a cube or the outlines of a room with labels, and updated them according to the user’s head position. Because the picture was made of lines and not filled surfaces, the effect was of glowing outlines floating in space, with the real room visible through the optics.
The image was only a few lines of vector graphics because computers of the time had limited speed. A specialized processor, sometimes described as a matrix multiplier, was needed to rotate and clip the shapes quickly enough. Calculating how a scene appears from a new viewpoint is exactly the kind of work later handled by graphics cards, which shows how much of the early effort went into computing rather than the headset itself.
Weight and tracking
The headset was too heavy to wear comfortably, so it was suspended from a mechanical arm fixed to the ceiling, which also measured the head’s position and orientation. This is the origin of the nickname: the arrangement looked precarious, although there is no sign that anyone was harmed. A second version used an ultrasonic sensing system to track the head. Both approaches were awkward, limited the user’s movement and needed a dedicated laboratory space.
In practical terms the system could only be used by one person at a time, had a narrow field of view, showed rudimentary graphics and required a room full of equipment. It was a research demonstration, not a product.
Claims of firsts
Several earlier or parallel developments are sometimes put forward as the true first, and each has some merit.
- Morton Heilig’s Telesphere Mask (patented around 1960) was a wearable stereoscopic viewer, but it showed film and was not interactive.
- Heilig’s Sensorama (early 1960s) was a booth for multi-sensory film, not a head-worn device.
- A remote-viewing system from the early 1960s, built with a helicopter manufacturer, used a camera that followed the operator’s head movements. It demonstrated head-coupled viewing but displayed a live camera image, not a computer-generated world.
- Sutherland’s display added computer-generated graphics to head tracking.
The honest conclusion is that VR had several beginnings. The term “first” is easiest to defend for computer-generated, head-tracked graphics, and Sutherland’s display is the standard example of that, with the caution that it built on contemporary work in graphics and display research.
Common misconceptions
Popular accounts sometimes overstate the result. The Sword of Damocles did not produce photorealistic worlds, it was not sold, and it was not used by a wide audience. Dates given for the work also vary: the 1965 paper, the 1968 report and later demonstrations are sometimes blurred together. It is safest to say that the work appeared in the second half of the 1960s.
Why it still matters
The display established a design that later systems kept: a screen near each eye, tracking of head movement and a computer redrawing the scene accordingly. It also exposed the problems that took decades to solve, namely weight, delay and the limited processing speed of the day. Researchers continued with these problems in laboratories and in military and space programs through the 1970s and 1980s, with commercial products appearing only decades afterward. The wider path from that work to the headsets of the 2010s is described in the overview of how VR headsets developed.