Whenever Balthasar Hacquet (?–1815) wrote about his origins and birth, he intentionally wrapped the issue into a mist of secrecy. In his autobiography, he claims to be born in 1739 or 1740 at Le Conquet (Finistère, Brittany, France) as an illegitimate son of an aristocrat, but we have no proof for this, in spite of detailed research done by Gérald Phillips. Nevertheless, this claim was adopted as whole truth by a vast majority of biographical texts on Hacquet. On the other side, during his stay in Ljubljana / Laibach (1773–1787), Hacquet obviously told the baron Sigmund Zois that he was an illegitimate son of a Russian potentate, which cannot be proved by sources and is ignored by international literature. In 1821, a well known German literary dictionary entitled »Das gelehrte Teutschland« published the third variant, i.e. that Hacquet was a military surgeon by profession and born in 1739 in the Lorraine city of Metz (Moselle, France). This possibility was partly taken into consideration by literature and becomes perfectly plausible through my research at the Archives municipales de Metz. However, the final decision on this hypothesis could be reached only through extensive further research.