Princess Maria Teresa de Borbón-Parma has become the first member of a royal family to pass away due to Coronavirus complications.

The Spanish princess' younger brother took to social media to announce the tragedy on Thursday.

"On this afternoon… our sister Maria Teresa de Borbón-Parma and Borbón Busset, victim of the coronavirus COVID-19, died in Paris at the age of eighty-six," Prince Sixtus Henry of Bourbon-Parma, the Duke of Aranjuez, said in a statement on Facebook.

According to the prince, a memorial service was held in Maria Teresa's honor on Friday in Madrid.

As some know, Maria Teresa was referred to as the "Red Princess" for her progressive views. She was an advocate of women's rights and had many socialist ideas.

As People reports, she was a beloved and renowned professor at Paris' Sorbonne and a professor of Sociology at Madrid's Complutense University. Moreover, the outlet points out she was an early supporter of CIVIS (the open university system, which ties schools in eight European nations) and studied Islam, particularly as it applied to women's rights in Arab nations.