While there was tension between them, Kepler did not engage in any form of theft.

Here's the actual story:

* Tycho Brahe was a renowned astronomer known for his incredibly accurate observations of the planets. He died in 1601.

* Johannes Kepler was a brilliant mathematician and astronomer who became Tycho's assistant in 1600.

* Tycho, however, was reluctant to share his data fully with Kepler, fearing he might use it to advance his own theories, which contradicted Tycho's.

* After Tycho's death, Kepler was appointed as the Imperial Mathematician, inheriting Tycho's data.

* The data was bequeathed to Kepler by Tycho's heir, not stolen.

Kepler used Tycho's data to develop his three laws of planetary motion, which revolutionized astronomy. This wouldn't have been possible without access to the data, but it was a legal inheritance, not a theft.

The story of Kepler stealing the data is a common misconception, likely fueled by the rivalry and tension between them.