How was the Diels Alder reaction discovered?

Here's my understanding of the story.

In the 1920s, Kurt Alder was Otto Diels' graduate student at Kiel University.

His project involved studying the reaction of cyclopentadiene with benzoquinone.

He discovered that cyclopentadiene reacts with benzoquinone to produce a 1:1 and a 2:1 adduct.

For this work, Alder received his doctorate in 1926.

In 1928, Diels and Alder jointly published a paper on the reaction of dienes with quinones.

They stated that they reserved the right to use this reaction in synthesis exclusively for themselves.

Luckily, no one respected that.

The reaction became widely used and gave rise to many important innovations.

It was the key step in the synthesis of many complicated natural products, such as cortisone, cholesterol, and many others.

For their pioneering work, Otto Diels and Kurt Alder were awarded the Nobel Prize in Chemistry in 1950.