Art Nouveau/Jugendstil silver and pewter made by JP Kayser & Sohn AG which was located in Krefeld, Germany. Opening their first foundry in 1844 they finally went out of business in 1930. In 1900 their work earned a gold medal at the Paris Exposition Universelle.

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Art Nouveau vase in white metal. ca. 1900. Designed and signed by Hugo Leven probably for J. P Kayser Sohn. Leven did a lot of their design work. Image © 2008-2020 Bukowski Auktioner AB. Fair use license. via https://www.bukowskis.com/en/auctions/581/489-a-hugo-leven-white-metal-art-nouveau-vase-probably-for-j-p-kayser-sohn-germany
Austrian-Jewel-Casket-a
Jewel casket. ca. 1900. Silver plate. Image © 2014 Dorian Frank. Fair use license. via https://www.dorianfrank.com/product/kayser-sohn-art-nouveau-jewel-casket/
Kayser-Art-Nouveau-Novelty-Silvered-Pewter-full-1A-700_10.10-53-f
Inkwell and pen tray, modeled as a bobsleigh with sculptured four men team on board. ca. 1900. Art Nouveau. Silvered pewter. Probably designed by W. Zwick. Marked with the Kayser and Sohn logo. Image © 1998-2020 Ruby Lane, Inc. Fair use license. via https://www.rubylane.com/item/1190085-0099-0931/Kayser-Art-Nouveau-Novelty-Silvered-Pewter