The costume is one which Columbus never wore.
In his youth Columbus was affiliated with a religious brotherhood, that of Saint Catherine, in Genoa.

In after times, on many occasions when it would have been supposed that he would be richly clothed, he appeared in a grave dress which recalled the recollections of the frock of the religious order of Saint Francis.

According to Diego Columbus, he died, "dressed in the frock of this order, to which he had always been attached." ***** The reader who has carefully followed the fortunes of the great discoverer understands from the history the character of the man.

He would not have succeeded in his long suit at the court of Ferdinand and Isabella, had he not been a person of single purpose and iron will.
From the moment when he was in command of the first expedition, that expedition went prosperously to its great success, in precisely the way which he had foreseen and determined.

True, he did not discover Asia, as he had hoped, but this was because America was in the way.