Complex sentence: During the last years of the regime, a strong desire for a representation of the Archipelago in the Spanish Cortes was prevalent among the Principales, especially among those who have studied in Spain and other parts of Europe (Ilustrados).
Split into simpler sentences: During the last years of the regime, there were efforts to push for a representation of the Archipelago in the Spanish Cortes among a good number of Principales. This move was prevalent especially among those who have studied in Spain and other parts of Europe (Ilustrados).