On 6 June 1935 Escher’s father received a letter from his son informing him that a rich architect had bought ten of his prints for 900 lire.* This sum was nearly enough to cover his trip to Sicily he was on at the time. It was a high point of what was to be a year of financial disaster for Escher.
After several years of hardship that preceded it, 1935 marked a new low. Escher’s work garnered praise and he held exhibitions regularly, but his sales were very disappointing. Especially in the Netherlands. It would be another 20 years before he would be selling large amounts of his work. It is not known which prints Escher sold to the architect. Coast of Amalfi, from November 1934, could easily be one of them.
Source
[*] M.C. Escher, His Life and Complete Graphic Work, edited by J.L. Locher, Abradale Press, 1982, page 40