Final answer:
The first four princes' gifts are similar as they are all made from precious materials, indicated by the descriptions of gilded and bejeweled items and the context of valuable courtship gifts.
Step-by-step explanation:
The gifts of the first four princes in 'The Princess and the Tin Box' are similar because they are all made from precious materials. This detail can be inferred from the provided passages that describe how the items are gilded, bejeweled, and the significance of the box in the context of courtship and marriage, which typically involves valuable gifts. The description of the items' impressive and luxurious characteristics further supports that they are made from materials of value.