The Royal Zuid-Holland Plateelbakkerij (Royal Zuid-Holland Plateel Factory) in Gouda produced pottery between 1868 and 1965. The factory is also known as Plazuid and PZH. The factory's products are generally referred to as Gouda plateel. Especially in the early period, Zuid-Holland produced what is known as glossy plateel in the Art Nouveau style. Later, matte glaze was the primary choice, and the designs became more modern. The factory's products are always marked with an image of the Lazarus Gate, a well-known monument in Gouda. The two nearly identical vases in the De Witte Zwaan collection are perfect examples of the Art Nouveau designs produced by Plazuid. The vases are shaped like amphorae with rectangular handles. They have a dark background with a somewhat whimsical image of tulips.