A succession of actions now took place on land, and the Paraguayans, although fighting with a desperate heroism, were gradually beaten back and driven across their own frontiers. At the same time, the army which had invaded Brazil retired in sympathy, and the scene of the war changed to Paraguay itself, which was in its turn invaded by the forces of the triple alliance. One of the most sanguinary battles of the war was fought on May 24, 1866--very nearly a year after the first naval action off the river port of Corrientes. At this Battle of Tuyuti the Paraguayans lost no fewer than 8,000 men, and the casualties of the allies amounted to an equal number. Another important action was fought at Curupaiti two months later, when the progress of the allies was abruptly checked, and they were compelled to retire to some distance with a loss of 9,000 men. This was only one of a fair number of Paraguayan victories, for the defenders, although in the main they preserved an attitude of strenuous resistance, were occasionally enabled to exchange this for active aggression. The history of this war, which lasted for four years, is one of the most remarkable in the whole category of struggles of the kind. Undoubtedly one of the most extraordinary features to be met with is the tremendous courage and grim determination with which the Paraguayans opposed the forces of the allies. Every yard of the country was contested with a fierceness which left the entire countryside covered with dead and wounded. When, moreover, the modern arms in the possession of which the Paraguayan armies had commenced the war had become lost and depleted in numbers, their place was taken by improvised weapons of all kinds, and it was frequently with the crudest firearms and lances that these devoted armies continued to fight. The encouragement these troops received from their leaders--or, rather, from Lopez--was in one sense of a negative order. Rewards for valour were unknown, but punishments for defaults, on the other hand, whether real or imaginary, were abundant and terribly severe. Men were shot for having in the course of private conversation uttered words which the suspicious mind of Lopez classed as discouraging. Thus a trooper was on one occasion executed for having ventured the remark that, although the Paraguayans rejoiced over the numbers of their enemies who were slain, they invariably forgot to count their own dead. A second soldier met with a similar fate for having, on his return from a reconnaissance, stated that the enemy lay in great strength to the front. Lopez conceived that a report such as this could serve no good end, and ordered its maker to be executed forthwith.