Johann Jacob Leu: magistrate, jurist and lexicographer

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Johann Jacob Leu was born in Zurich on 26 January 1689, the son of Hans Jacob Leu, a member of the council and bailiff, and of Dorothea Heidegger.¹ As a pupil of the naturalist Johann Jakob Scheuchzer he joined an Alpine expedition in 1705. He then travelled through Germany between 1707 and 1709, studying law and natural law at Marburg, and spent the winter of 1708–1709 in the Netherlands and Paris, keeping a detailed diary of the journey. The combination was characteristic of the Zurich elite of the early Enlightenment: a grounding in the natural sciences under Scheuchzer, a legal education at a German Protestant university, and first-hand acquaintance with the commercial and financial capitals of the time, Amsterdam and Paris.

His career in the service of the republic proceeded through the classic stages. He entered the chancery in 1709, became librarian of the civic library in 1710, council substitute in 1713 and city secretary (Stadtschreiber) in 1729. From 1736 to 1742 he served as bailiff (Landvogt) of Kyburg, one of the most important of the rural bailiwicks. In 1749 he became Seckelmeister, treasurer of the state, before his election as burgomaster of Zurich in 1759.² The Neue Deutsche Biographie dates the Kyburg bailiwick from 1735 and gives 10 September 1768 as the date of death. Such discrepancies are minor, yet they illustrate how even the basic data of eighteenth-century officeholders can vary between reference works.³ The offices that matter for this chapter are those of treasurer and burgomaster: when the Zinskommission was founded, Leu was the officer responsible for the finances of the state and remained its president after rising to the highest office of the republic.

Leu is remembered in Swiss cultural history for a different achievement. Between 1747 and 1765 he published the Allgemeines Helvetisches, Eydgenössisches oder Schweitzerisches Lexicon in twenty volumes, the first complete and comprehensive Swiss encyclopaedia, a work that he financed largely himself. The Lexicon is the direct ancestor of the Historical Dictionary of Switzerland cited throughout this book. It would be hard to find a more fitting founding figure for a bank that was to live for more than two and a half centuries: a man who catalogued the families, places, institutions and offices of the Confederation with the same care that a banker applies to a register of debtors. Leu was also a jurist of standing. Between 1727 and 1746 he published a four-part treatise on Swiss private law, the Eidgenössisches Stadt- und Landrecht, and re-edited Josias Simler’s classic account of the Swiss constitution.⁴

The juxtaposition of the lawyer, the historian and the treasurer has an inner logic. The Swiss private law that Leu set out in his Stadt- und Landrecht was, to a large extent, the law of land charges, annuities, guardianship and pious foundations: the legal forms in which wealth was held and transmitted in the old Confederation. The man who systematised the law of Gülten and Schuldbriefe was also the man who understood how much capital lay idle in the hands of guardians, guilds and foundations. The later tradition of the bank attributed to him the motto “Selbst im Schlaf bin ich wach”, “even in sleep I am awake”, which Credit Suisse still quoted at the bank’s two hundred and fiftieth anniversary in 2005.⁵

Leu did not act alone. His principal partner in the enterprise was Hans Conrad Heidegger (1710–1778), a generation younger, who had studied modern languages at Lausanne and Neuchâtel in 1729 and had spent a formative period in Berlin, where he encountered what the Historical Dictionary calls an exemplary administration. Heidegger entered the Great Council in 1741 for the smiths’ guild, became a member of the Small Council in 1752, salt administrator in 1754, privy councillor in 1757, treasurer in 1759 in succession to Leu, and burgomaster in 1768. He was the driving force behind the Zurich school reforms of 1765–1773 and in 1777 negotiated the alliance between France and the Swiss cantons. The Historical Dictionary credits him with having helped to establish Leu & Co. in 1755 as a means of creating investment opportunities abroad for Zurich capital.⁶ The founding pair thus combined the senior treasurer and the rising administrator of the Prussian-influenced reform generation. The later historiography of the bank consistently names both of them as founders.⁷

Notes

1. HLS, Marianne Zelger-Vogt, “Leu, Johann Jacob”, version of 25 November 2008, https://hls-dhs-dss.ch/de/articles/015795/2008-11-25/ (also accessible at https://hls-dhs-dss.ch/textes/d/D15795.php). The article gives his dates as 26 January 1689 to 10 November 1768 and lists his marriages to Anna Magdalena Hofmeister (1713) and Dorothea Ott (1749). ↩
2. HLS, Zelger-Vogt, “Leu, Johann Jacob”, cited above. The article states that he presided over the interest commission founded in 1755, which appeared publicly as Leu & Cie. and later became Bank Leu. ↩
3. Schmid, “Leu, Johann Jakob”, NDB 14 (1985), cited above. ↩
4. HLS, Zelger-Vogt, “Leu, Johann Jacob”, cited above, which describes the Lexicon as “das erste abgeschlossene, umfassende Schweizer Lexikon” and mentions the edition of Simler; Schmid, NDB 14 (1985), cited above, notes Leu’s personal financing of the Lexicon and describes the Eidgenössisches Stadt- und Landrecht as a comprehensive presentation of Swiss private law in four volumes. A modern study is Claudio Soliva, Das Eidgenössische Stadt- und Landrecht des Zürcher Bürgermeisters Johann Jakob Leu, 1969, listed in the HLS bibliography. ↩
5. Toni Saller, “The Big Sleep: Die Bank Leu, Teil vier”, Inside Paradeplatz, 21 January 2019, https://insideparadeplatz.ch/2019/01/21/the-big-sleep-die-bank-leu-teil-vier%EF%BB%BF/. ↩
6. HLS, “Heidegger, Hans Conrad”, http://www.hls-dhs-dss.ch/textes/d/D18058.php. The article gives his dates as 12 January 1710 to 2 May 1778. ↩
7. HLS, Baumann, “Bank Leu”, cited above, which names Leu and Hans Conrad Heidegger as co-founders; to the same effect Hans Fässler, letter to Walter B. Kielholz, Chairman of Credit Suisse Group, 10 December 2007, https://archiv.louverture.ch/KAMPA/KRITIKEN/kielholz.html. ↩

For general information only. This article does not constitute legal or tax advice, does not replace advice on an individual case and creates no lawyer-client relationship. It reflects the legal position as of September 2025.