Sun of May

The Sun of May (Sol de Mayo) is one of the national emblems of Argentina and Uruguay, appearing on both countries’ national flags and coats of arms. It takes its name from the May Revolution of 1810, which marked the beginning of the independence process in the Viceroyalty of the Río de la Plata. The sun is commonly interpreted as a symbol of the birth of a new nation, a meaning also reflected in the Argentine National Anthem approved by the Assembly of the Year XIII in 1813.

The first official use of the sun as a national symbol occurred in 1813, when the Assembly of the Year XIII adopted it on its seal (later the basis of the Argentine coat of arms) and on the first national coins minted in Potosí. The design is generally attributed to the Cuzco-born engraver , working under commission from the Assembly. The sun was added to the Argentine war flag on 25 February 1818 by decree of the Congress under Supreme Director Juan Martín de Pueyrredón.

The design consists of a golden disc with a human face, from which rays emerge alternating between straight and wavy (flaming). The Argentine version has 32 rays (16 straight and 16 wavy), while the Uruguayan version follows the more common European heraldic convention of 16 rays.

It is frequently claimed that the Sun of May represents Inti, the Inca sun god. This interpretation, popularized mainly by the historian Diego Abad de Santillán in the 20th century, lacks contemporary documentary support from the revolutionary period. No primary sources from 1813–1818 explicitly identify the emblem with Inti. The design is more accurately understood as deriving from the long-established European heraldic charge known as the “sun in splendour” (a face surrounded by alternating straight and wavy rays), which was already common in Spanish and European iconography, including ecclesiastical and military uses in the colonial period. Some authors have also noted possible Masonic influence, given the prominence of Freemasonry among the revolutionary leadership (including Belgrano and San Martín) and the sun’s traditional association with light and reason in Masonic symbolism.

Throughout the rest of the 19th century, the sun appeared in numerous distinct designs on flags, notably in red during the government of Juan Manuel de Rosas, as well as on coins, with significant variations across each province. At the beginning of the 20th century, historical studies on the flag and coat of arms emerged, with proposals aimed at aligning the sun's design with that of the 1810s. However, it was not until 1944 that a definitive regulation was established, finalizing the design of the Sun of May based on the first national coins of 1813. Finally, in 1985, it was established that the only Argentine flag was the one with the sun, eliminating the obligation for civilians to use the sunless version.

In the case of Uruguay, it was constituted as a country in 1828 at the end of the Cisplatine War, which confronted the United Provinces of the Río de la Plata and the Empire of Brazil for the control of the Banda Oriental, and chose national symbols linked to those of Argentine independence. Similar to the Argentine case, the sun used in Uruguay's coat of arms and flag underwent numerous variations until its current design was formalized in 1952. This decree also standardized the color of the flag's stripes as blue, distinct from the light blue used in Argentina's flag.