Born in Recife, Pernambuco, Hermenegildo was the son of Luís da Costa Ferreira and Ana Teodora Pita Portocarrero de Melo e Albuquerque.

However the fort was surrounded by a force of 5,000 Paraguayan infantry, transported in ten ships by Colonel Vicente Barrios at Asunción.

Portocarrero was given an ultimatum to surrender but he refused, stating that he would fight to the last cartridge, despite the inferiority of men and weapons.

[2] After two days and a night of incessant bombardment, and unable to face the enemy forces, the small garrison, protected by darkness, abandoned the fort and boarded the speedboat Amambaí, which went to Cuiabá.

[3] Hermenegildo himself broke the news of the invasion of the fort on January 6, 1865, to the governor of the province Alexandre Manuel Albino de Carvalho [pt].