In 1669 Hennig Brand, a merchant and physician of Hamburg with an interest in the philosopher's stone, reasoned that human urine, being golden, might contain the principle of gold. He collected it in quantity, by some accounts more than a thousand litres, let it putrefy, boiled it down to a syrup and distilled the residue at high heat. What came over and condensed was not gold but a white waxy solid that glowed steadily in the dark without burning, and caught fire on its own in warm air.
He called it cold fire. The name that stuck, phosphorus, is Greek for light-bearer and had previously been a name for the morning star.
This is the first discovery of an element by an identifiable person in a recorded experiment, and it belongs to alchemy rather than to chemistry, which is exactly why it matters here. Brand's method was secret and he sold it; Johann Kunckel and Daniel Kraft acquired it and made money exhibiting the glow at courts across Europe. Robert Boyle, who saw a demonstration, worked out a preparation of his own by 1680 and, unlike the others, published it.
Brand was searching for the wrong thing by reasoning that was wrong, and he found something genuinely new. That is a fair description of a good deal of alchemical practice, and it is a better defence of the tradition than any claim about hidden wisdom.
The glow itself is not combustion. White phosphorus reacts slowly with oxygen at its surface, producing an excited intermediate that emits light, a process now called chemiluminescence. The word phosphorescence, which in modern usage means something different again, took its name from this substance by an accident of history.