Definition:Orthogonal Trajectories/Historical Note

Historical Note on Orthogonal Trajectories
The origin of the problem of orthogonal trajectories is uncertain.

Some sources say that it was posed by in $1720$ as a challenge to the English  school of mathematics.

Others suggest that it was the work of in $1716$, who was aiming the problem specifically at  himself.

Legend has it that solved the problem in an evening, having returned from his day's work at the Mint.