[2][3] One of the first politically outspoken Argentine women, Mariquita Sánchez de Thompson has been considered the most active female figure in the revolutionary process.

[2][4][3] At 14 years old, Sánchez expressed her desire to marry 23-year-old Martín Jacobo de Thompson, her second cousin on her mother's side.

[5] Thompson was a sailor and officer in the Spanish Royal Navy, educated in Europe, and held strong pro-independence ideas.

[5] Her father used his political connections within the Royal Navy to transfer Thompson to Spain and send Sánchez to the Casa de Ejercicios, "a place of physical seclusion and spiritual meditation frequently used by parents to punish and persuade their wayward daughters.

[6] Sánchez successfully appealed to Viceroy Sobremonte in an 1804 letter, arguing against the predominant custom of marriages being arranged by families without the consultation of the women involved.

"[2] She contributed to the Argentine independence cause, in 1810, by donating three ounces of gold (equivalent to approximately 4800 U.S. dollars in 2020) and in 1812, by sewing uniforms for the "patriot army.

"[2] Sánchez hosted tertulias, social gatherings similar to salons, that were some of the most renowned in all the Viceroyalty, and which were attended by many aristocrats and officials of the time.

[9] Her writing has been characterized as masterful, as a result of her well-educated childhood, with her works being widely received as having a "civilized and enlightened spirit.

[10] Sánchez's works carried prominent themes of feminism, exploring it from the aspects of equality, education, and female sexual conduct's influence on politics.

[6] Sánchez is remembered largely for her political activism and advocacy for women, including her involvement with the Sociedad de Beneficencia.

[2][3] Sánchez is also thought to have been the first person to sing the Argentine National Anthem—which was said to have been sung for the first time at her house 14 May 1813—a claim that even appears in elementary school textbooks.

[13][14] The nature of Sánchez's relationship with Mendeville has been called into question, as some accounts have her married and pregnant with his child in 1819, the same year that her previous husband Thompson died.