These are twenty-nine-inch platform shoes, called chopines, from sixteenth-century Venice. According to the Metropolitan Museum of Art:
Developed in the early sixteenth century and especially popular among Venetian women, the high-platformed shoe called the chopine had both a practical and symbolic function. The thick-soled, raised shoe was designed to protect the foot from irregularly paved and wet or muddy streets. But the enhancement of the wearer's stature also played a role.
The chopine's height introduced an awkwardness and instability to a woman's walk. The Venetian woman who wore them was generally accompanied by an attendant on whom she would balance. Despite the obvious expense, Venetian sumptuary laws (laws regulating expenditure on luxuries) did not address the issue of exaggerated footwear until it reached dangerous proportions. It was once thought that very high chopines, twenty inches as seen in the example from the Museo Correr di Veneziani, were the accoutrements of the courtesan and were intended to establish her highly visible public profile. However, sixteenth-century accounts suggest that the chopine's height was associated with the level of nobility and grandeur of the Venetian woman who wore them rather than with any imputation as to her profession.