The first Marteau books were French and most certainly printed in Amsterdam by publishers who would not risk to tell their names even in the Netherlands. Research has hinted at Amsterdam publisher Elzevier as the man who invented the imprint. It was, at first, just one among many openly misleading imprints. Unlike the usual obvious pseudonyms like "Jacques le Sincere", the name "Pierre Marteau" sounded real. The detail which gave away his virtuality remained on the reader's side — he would identify Cologne as the likely and yet unlikely place to go. "Hammer" made the joke a little bit more explicit: this man had courage and he was as real and as bold as a hammer.