In another incident, in eighteenth-century Amsterdam, members of the Spanish-Portuguese community were excommunicated for being Karaites.
These heterodox Sephardim had been exposed to the idea of Karaism by way of the literature of Christian Hebraism, rather than through contact with real Karaites.
The problem is analysed by Yosef Kaplan in The “Karaites” od Amsterdam in the Early Eighteenth Century: An Unknown Chapter in the Fermentation of Ideas in the Sephardic Community; revised and published in English as “Karaites” in Early Eighteenth-century Amsterdam.

Fred Astren, Karaite Judaism and Historical Understanding, 223