This process, at work throughout Lombardy, is shown in the second half of the thirteenth century in Milan by the gradual narrowing of the general party issue into a struggle for predominance between two great Houses, who represent and sum up in their mutual quarrel the diverse aims of the factions, and divide the community into two sharply defined and bitterly hostile bands, which fall inevitably, though by no means very precisely, into the wide general division of Guelf and Ghibelline. These were the Houses of the Della Torre, or Torriani, and of the Visconti. In the race for supremacy the first far outstripped the second. The Della Torre were country nobles, who had, however, long been subjects and citizens of Milan, and though living usually on their estates in the Valsassina, they often appeared in the city and took part in its government and politics. They are named among the Capitani—the great secular nobles of Milan—from early in the twelfth century. They had from the first aided and protected the cause of the people against their own order, and it was this sympathy which lifted them to greatness on the democratic wave of the thirteenth century. The power of this House in Milan arose first out of the gratitude of the city for the compassionate succour which Pagano della Torre, head of the House in 1237, gave to the wounded and starving fugitives from the disastrous battle of Cortenuova, whom he sheltered and tended in the Valsassina, and afterwards helped to get back safely to Milan. The Commune rewarded him with offices and with gifts of houses, and from that time the Torriani became regular inhabitants of the city and the principal leaders of the people’s faction.