The news of Mateo's availability spread through European football circles with the speed and intensity of wildfire, creating a phenomenon that surprised even the most experienced observers of the transfer market.
Within a week of the story breaking, Casa de los Niños became an unlikely hub of international football activity, as representatives from some of Europe's most prestigious clubs sought to arrange meetings with the young player who had been cast aside by Barcelona.
Don Carlos found himself in the unusual position of managing what amounted to a diplomatic mission, as coaches, sporting directors, and agents from across the continent expressed their interest in Mateo's future.
The elderly man's study became a war room of sorts, with maps of Europe spread across his desk and files containing detailed information about various clubs and their approaches to player development.