A single misheard phrase over the mountains of Washington state in June 1947 helped turn ‘flying saucer’ and UFO lore into a global obsession, after pilot Kenneth Arnold reported seeing nine inexplicable objects near Mount Rainier and a local reporter twisted his description into the shape that would define the phenomenon.

People had been seeing strange things in the sky for as long as they’ve been looking up. Ancient texts are cluttered with what we’d now casually label UFO sightings, long before anyone had a word for them.

The prophet Ezekiel wrote of a wheeled chariot filled with heavenly beings; Hindu epics describe airborne chariots of the gods; and the Roman historian Livy noted that, in the winter of 218 BCE, ‘a phantom navy was seen shining in the sky.’ In other words, the 1947 sighting did not invent mysterious lights. It reframed them.

Centuries later and an ocean away from Mount Rainier, early colonial America had its own share of unsettling reports. In 1639, John Winthrop, then governor of the Massachusetts Bay Colony, recorded in his diary that three men rowing on a river saw a ‘great light’ appear above them. When it hung still, Winthrop wrote, it ‘flamed up’ and grew to about three yards square. When it moved, it drew in on itself ‘into the figure of a swine.’

The light, he noted, drifted around for two or three hours. When it finally vanished, the three men discovered they were mysteriously a mile upstream from where they started. Winthrop went out of his way to add that ‘diverse other credible persons’ saw the same light in roughly the same place. In later entries, he mentions more odd celestial displays, such as a ‘light like the moon’ that rose over Boston and spat out ‘flames and sometimes sparkles.’

Native American nations, whose stories predate Winthrop by millennia, have their own extensive accounts of strange beings and sky phenomena. Those narratives are rarely treated with the same seriousness as a governor’s diary or a military memo, but they form a continuous backdrop to the more recent UFO stories that the West elevated and named.

The phrase UFO only entered popular usage in the early 1950s, as a more sober replacement for ‘flying saucer.’ That older term has roots in a single afternoon: 24 June 1947. The skies were clear and visibility was excellent when businessman and civilian pilot Kenneth Arnold took his small plane up near Mount Rainier at about 3 p.m.

What followed was, by any standard, bizarre. Arnold reported seeing nine objects, each flashing a bright blue‑white light, flying in a loose V formation above the Cascade Range. He later calculated that they covered the roughly 50 miles from Mount Rainier to Mount Adams in about 1 minute 42 seconds. Some estimates put that at around 1,700 miles per hour, a speed that was well beyond any publicly known aircraft at the time.

Read More: The ‘flying saucer’ is a lie: How a 1947 media misquote changed UFO history forever