Flag of the Argentine Confederation, represented by Buenos Aires Province.
SVG based on File:Bandera argentina buenos aires argentina 1852.png https://archive.ph/8UyiW/0255393d5c3ab4c5e033b77d761673da8b963b6b.webp
Juan Manuel de Rosas (1793–1877), according to La Gazeta website  (vector graphics by Guilherme Paula)