4. We know, because Theo recommended his doctor to him, that
Koning initially had problems with his health.
See letter 578, n. 9. As we can deduce from a letter from Koning to Theo, they took their leave of each other at the Gare du Nord on 28 May 1888. Koning was then ‘in an anything but cheerful mood’; he travelled back to Winschoten via Bruges, Ghent, Dordrecht and Rotterdam, arriving home on 2 June (FR b1077).