Manuel Belgrano's decision to create a national flag was, in the political logic of 1812, an act of insubordination. The First Triumvirate governing Buenos Aires was still officially claiming to rule on behalf of Ferdinand VII, the Spanish king held captive by Napoleon. Creating a new flag was an unmistakable declaration of independence — exactly the message the cautious government wanted to avoid. Belgrano did it anyway. On February 18, 1812, the Triumvirate approved a new cockade in white and light blue, and nine days later, Belgrano raised a flag of those same colors at the Bateria Libertad along the Parana River in Rosario. When the Triumvirate ordered him to stop using the flag, the message arrived too late. Belgrano had already marched north to reinforce the Army of the North in Upper Peru, and at San Salvador de Jujuy, he had the flag blessed by the local church on the second anniversary of the May Revolution.

The Second Triumvirate, more liberal in its outlook, authorized the flag as a war banner in early 1813 through the Asamblea del Ano XIII. The first oath to the newly sanctioned flag took place on February 13, 1813, beside the Salado River — a ceremony so significant that the waterway became known as the Rio Juramento, the Oath River. The Battle of Salta followed, a decisive patriotic victory that crushed royalist commander Pio Tristan's forces. But momentum reversed quickly. At Vilcapugio and Ayohuma, the independence army suffered devastating defeats, and Belgrano's forces retreated south through the harsh Andean landscape. Fearing that pursuing royalist troops would seize the standards as trophies, Belgrano entrusted them to the parish priest of Macha, who concealed them behind a religious painting in a small chapel near Titiri.

Belgrano was recalled to Buenos Aires and sent to Europe on a diplomatic mission. The flags he had created, fought under, and hidden were presumed lost. Decades passed. Bolivia became an independent nation in 1825. The chapel at Titiri continued its quiet existence in the highlands north of Potosi, and the portrait of Saint Teresa kept its secret. Then in 1885, a priest undertaking renovations discovered the two silk banners. They were transferred to the Museum of the Independence in Sucre, where Bolivia kept one. Argentina's ambassador to Bolivia, Adolfo Carranza, requested the return of the other, and in 1896 it was delivered to the National Historical Museum in Buenos Aires. A curious detail divides them: the flag Argentina holds is a triband of blue, white, and blue, matching the modern Argentine flag, while the one Bolivia kept is white, blue, and white.

By the time conservators at the National Historical Museum began restoring the Argentine flag in 2007, only seventy percent of the silk remained. Maria Pia Tamborini and Patricia Lissa led the painstaking work, studying fibers that had spent centuries in conditions no textile was meant to endure. The original colors — indigo blue and ivory white — had faded beyond recovery. Today the flag rests in a closed cabinet in a low-light room, shielded from the damage that air and illumination would inflict on what remains. In 2010, the year Argentina celebrated its bicentennial, the flag was displayed publicly for the first time. That same year, Tucuman Province adopted the Macha flag as its official provincial emblem, linking a modern Argentine province to a silk banner that a revolutionary general hid in a Bolivian church two centuries earlier.