Clay groups depicting the Virgin and Child, Saints Catherine and Barbara were a speciality of Utrecht. These figurines were made in large quantaties using moulds, and were dispersed all over Europe. The clay used was easy to cast, however the result was very breakable making these figures quite scarce today. See J. Leeuwenberg and W. Halsema-Kubes Beelden in het Rijksmuseum, Amsterdam 1973, pp. 46-47 and 498-501.