17th March

On this day in 1694, Guillaume de l'Hôpital sent a letter to Johann Bernoulli with a remarkable proposition:-
I will be happy to give you a retainer of 300 pounds, beginning with the first of January of this year. ... I promise shortly to increase this retainer, which I know is very modest, as soon as my affairs are somewhat straightened out. ... I am not so unreasonable as to demand in return all of your time, but I will ask you to give me at intervals some hours of your time to work on what I request and also to communicate to me your discoveries, at the same time asking you not to disclose any of them to others. I ask you even not to send here to Mr Varignon or to others any copies of the writings you have left with me; if they are published, I will not be at all pleased. Answer me regarding all this ...