Jewish financier of Ulm in the fourteenth century; married the daughter of the "Grossjuden" Moses of Ehingen. Jäcklin had several sons; one of them, Isaac, lived in Strasburg, another in Riedlingen, or Reutlingen, and a third, Veflin, in Nuremberg. Jäcklin was probably president of the Jewish community of Ulm for many years; he loaned considerable sums to the municipal government of Ulm and to the counties of Helfenstein, Altenbeck, and Werdenberg. For example, he advanced (Oct. 1, 1378) to the community of Ulm 1,680 gulden for the redemption of the monastery of Langenau, receiving 84 gulden interest semiannually; and later, 1,800 gulden, receiving the gate-toll of the city in payment. On Nov. 13, 1378, the council of Ulm entered into an agreement with Jäcklin to declare void all the documents bearing upon the city's indebtedness to him, excepting those relating to the two loans mentioned. A letters patent ("Tedingbrief") has been preserved which gives him the right to remain in Ulm until Dec. 6, 1379.
Eberhard der Greiner (= "the complainer") of Württemberg taxed Jäcklin 4,000 gulden, which he refused to pay. Thereupon Eberhard sued him and won his case before the court of Nuremberg (1376); the wife and son of Jäcklin were put into the "Reichsacht" by the emperor (Charles IV.) until the 4,000 gulden were paid (Sept. 5, 1376). It seems that Jäcklin nevertheless continued to live in Ulm. The "Reichsacht" directed against Ulm as also against Jäcklin was annulled by the Reichstag of Rothenburg May 31, 1377. On Oct. 6, 1376, in consideration of the damage done to the county of Heinrich von Würdenberg, the emperor declared void his debts to Jäcklin. The city of Ulm, however, reimbursed Jäcklin by paying him from 1378 onward, in half-yearly instalments, 10 per cent interest on Heinrich's debts.
- Pressel, Gesch. der Juden in Ulm, p. 31;
- Nübling, Die Judengemeinden des Mittelalters, pp. lxviii., 327 et seq.