Haarlem02 Statue of Laurens Jansz Coster. According to the Dutch, he invented movable type 10 years before Gutenberg. There is a tradition that, sometime in the 1420s, he was carving letters from bark for the amusement of his grandchildren, and observed that the letters left impressions on the sand. He is said to have printed several books including 'Speculum Humane Salvationis' with several assistants including Johann Fust, and it was Fust who, when Laurens was nearing death, stole his presses and type and took them to Mainz where he entered partnership with Johann Gutenberg.