The parlor of the Leu Interest Commission, founded in 1755 as the first bank in Zurich, was located on the right side of the first floor of Zurich City Hall. It was named after its treasurer Leu, as was fashionable among French private banks at the time. The bank was established to lend the large amounts of money that had accumulated among the citizens of Zurich. Loans were given to French and Danish slave trading companies, amongst others, which used them to finance their risky and profitable triangular trade.

The transatlantic slave trade began around the middle of the 16^th century. In the 17^th century, it developed into a triangular trade between West Africa, the Caribbean, and Europe. Europeans exported woven fabrics, alcohol, and weapons to Africa and "traded" them for black enslaved people, most of whom were kidnapped and sold by local slave traders. The European slave traders, in turn, had the enslaved people transported to the Americas by ship. The Atlantic crossing was very dangerous, costing up to half of the enslaved and a quarter of the crew’s lives. The surviving enslaved people worked on plantations in the Caribbean, Brazil, or in the southern states of the US, where sugar, rum, cotton, and tobacco were grown and produced for export to Europe, where they were sought-after luxury goods (see Kirchgasse 32). At the beginning of the triangular trade in the 17^th century, some lending companies achieved returns of up to 800%. Slavery was not officially abolished until the 19^th century.

New historical research shows that Swiss citizens and companies in colonial countries also exploited enslaved people, and regarded them as commodities. Numerous Zurichers were directly or indirectly involved in the slave trade and slavery: The Zurich pastor Heinrich Grob, for example, exploited enslaved people in South American Surinam. The Zurich physician Theodor von Muralt, who had emigrated to Brazil, was also a slave owner. After his death in 1863, enslaved people were mentioned by name in his will as possessions alongside animals and various pieces of furniture. 

Another example is Jakob Christoph Ziegler, whose divorce and bankruptcy earned him a bad reputation in Zurich - a common reason for leaving one’s hometown at that time. He traveled to the Dutch East Indies (now Indonesia) as a mercenary, and later took a post in the colonial administration on Sumatra where he "owned" three enslaved people. In a letter to his mother in Zurich, he reported: „Auch kaufte ich mir um diese Zeit eine Sclavin ein Mädchen von ungefähr 17 – 18 Jahren, für 40 Spanische Thalers, welche ich kochen, waschen, glätten und alles was zu einer Haushaltung nöthigist, lernte. Ausserdem versieht sie auch den Dienst als Frau, und ich bin in allen Rücksichten damit sehr zufrieden. Ich habe überdies noch zwey männliche Sclaven zum Wassertragen, Holz hacken und so weiter. Der Unterhalt dieser Unglücklichen ist unbedeutend und besteht aus Reis und Salz. Ein paar frische, getrocknete oder gesalzne Fische sind Leckerbissen für sie.“ ("At this time I also bought a slave girl of about 17 - 18 years, for 40 Spanish thalers, whom I taught to cook, wash, iron, and everything that is necessary for housekeeping. In addition, she serves as a wife, and I am very satisfied in all respects. I also have two male slaves to carry water, chop wood, and so on. The maintenance of these unfortunate people is insignificant and consists of rice and salt. A few fresh, dried, or salted fish are delicacies for them."

Some Zurichers owned plantations in the Caribbean, ‘employing’ enslaved people. In addition, wealthy Zurich citizens such as the theologian Leonhard Meister, the Escher family, the Usteri brothers, as well as the private bank Hottinger, invested in the slave trade. The city of Zurich itself owned shares of an English slave trading company in 1727.

This shows that Zurichers, and Zurich, had closer ties to slavery and the slave trade than we might like to admit. It is shocking that hardly anyone in Zurich questioned slavery as an inhuman institution, but rather understood it as a natural part of the European colonial system of trade and oppression. According to recent research, Swiss citizens of the old Confederation were involved in the enslavement of about 172,000 people, accounting for 1.5% of the estimated 11 million people enslaved in total. A high number for a country that was not a naval power and never officially had colonies.

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