1. Van Gogh could have meant two things here: both literally ‘drawing impossible windmills’ (drawing windmills does figure later in the letter) and figuratively ‘getting ideas that are impossible to achieve’ (cf. ‘drawing castles in the air’).

2. Van Gogh worked for Goupil & Cie in London from June 1873 to May 1875. Cf. in this regard also letter 39 and the little sketch after a view of London by De Nittis.

3. Van Gogh had once asked Maris if he would be his teacher. Maris must have told him that ‘you would have an odd one in me’, to which Van Gogh replied that that was exactly what he needed. Letter from Matthijs Maris to P. Haverkorn van Rijsewijk. See Heijbroek 1975, p. 282, and n. 154.

4. See for Marinus Boks’s madness: letter 307, n. 11.

5. Expression derived from Luke 9:62.

6. Theo joined Goupil in 1873 at the age of 15.

7. This expression is taken from Michelet; see letter 143, n. 2.

8. Willemien had already posed for him; see letter 168.

9. The question of whether or not to become a painter came up in letter 274 of 22 October 1882.

10. Possibly an allusion to the impending takeover of Goupil by Boussod and Valadon in 1884.