One of the panels in the Altarpiece of Caparroso
Cathedral of St. Mary, Pamplona, Spain
Though hardly alone in focusing the Pentecost event on Mary, this composition goes the extra mile in iconographically associating the event with the Annunciation. The Holy Spirit is placed ambiguously: is He winging toward the apostles or hovering over Mary? She has been interrupted in prayer, with a book on her lap, as in the Egerton Annunciation, a Spanish MS. of the previous century. The book may represent the Word that did so recently sit on the lap of the virgin mother. (See also Botticelli's Annunciation, another common type, in which the Virgin kneels with a chair behind her and the book is positioned on a prie-dieu before her.)
Read more about Pentecost.
Photographed at the cathedral by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.