The support of Queen Isabella was essential to Columbus's expedition. Though the subject of the 1-dollar stamp suggests that Queen Isabella sold her jewels to fund Columbus's expedition, in reality the Queen offered limited financial support. However, her decision to endorse Columbus’s voyage in the name of Spain made the discovery of the “New World” possible.
The portrait of Queen Isabella on the 4-dollar stamp is the first portrait of a woman to appear on a US postage stamp.