20 Pesos Regent Queen Maria Cristina

The Banco Español de Puerto Rico was established by royal decree in 1888 as the island's sole bank of issue, operating under Spanish colonial authority at a moment when Cuba and Puerto Rico were the last significant remnants of Spain's American empire. This note was produced by the American Bank Note Company — a routine commercial arrangement that Spanish colonial banks maintained with New York printers throughout the late 19th century, geography and politics notwithstanding.

The regency of Maria Cristina of Austria ran from 1885 until Alfonso XIII came of age in 1902, and the titular designation on this series reflects that administrative reality. Puerto Rico passed to the United States in December 1898 under the Treaty of Paris, rendering the banco's notes obsolete almost immediately — a circulation window of just a few years for any note dated toward the end of this range.