This small panel depicts an episode from the life of the Dominican tertiary and mystic, Saint Catherine of Siena. Upon arriving at church late one day because of her difficulty walking, Saint Catherine was dissuaded by her companions from taking communion because they knew her ensuing ecstasy would last for several hours. She concurred but prayed for God's help in receiving the Eucharist. Miraculously, an angel took a piece of the consecrated host and gave it to the saint. Celebrating Mass at a side altar, her confessor looked around with concern for the missing piece of the host. Neither he nor the others could see the miracle, so their expressions reflect bewilderment.
This panel and its companion, Saint Catherine of Siena Receiving the Stigmata, were probably made for the predella of an altarpiece dedicated to the saint.