John of Kastav (Latin: Johannes de Castua; Slovene: Janez iz Kastva) was a 15th-century Istrian artist, a native of Kastav (Croatia).
He painted the frescoes in the Church of the Holy Trinity, Hrastovlje, which included a famous Danse Macabre. According to the inscription, which identifies the artist as magister Johannes de Castua, the frescoes were commissioned in 1482, and completed in 1490.
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