These objects were used in the traditional Rite of Canonisation, where gifts of bread, wine and doves were offered to the Pontiff.
An example of this can be seen - albeit in a stylised form - on the tomb of Pope Alexander VIII in St. Peter's, where the canonisation of five Saints is represented, which he performed in 1690:
The Saints canonised on that occasion were Sts. John of God, Paschal Baylon, Lawrence Justiniani, John a S. Facundo, and John of Capistrano, all of which are still celebrated in the calendar of the usus antiquior, but only two of them - St. John of God and St. John of Capistrano - remain in the Roman calendar of the newer form.
An excellent description and explanantion of this depiction on Pope Alexander's monument in the Vatican Basilica and of the rites themseves can be found in the book by Edward J. Olszewski, Cardinal Pietro Ottoboni (1667-1740) and the Vatican Tomb of Pope Alexander VIII, Philadelphia, 2004. Here is an excerpt of that book, regarding the rites of the canonisation and the objects seen above and their depitction on Pope Alexnader's tomb (click to enlarge):
Another representation of this oblation at a canonisation, including the objects seen above (although in different forms), can be seen on this fresco from one of the rooms adjacent to the Apostolic Library in the Vatican:
Another example is found at the Roman church of "Il Gesù", presumably showing the canonsation of St. Ignatius:
Finally, the very same objects as shown the beginning of this post can seen in these photographs from the canonisation of the Uganda Martyrs by Paul VI in 1964:
Image Sources: John Sonnen, Ceremonia y Rúbrica, www.saintpetersbasilica.org
