I have become fascinated with vintage Polish illustration and recently purchased a few children's books on Ebay. Here are 2 versions of the same story. The name translates (according to google) as "As it was with Flax". It is also translated as "The Golden Seed". It is a story of long ago about a stubborn King who wished for gold, written by Maria Konopnicka.
The first one, dating from 1970, is illustrated by Bogdan Zieleniec. I can't find anything about the illustrator in English but I particularly like the horses.
The second one dates from 1962 and was illustrated by Janina Domanska (it is for sale in my Etsy shop here). I love the cover of this version.