Complex sentence: However, despite their efforts to defeat the Comanches, Spaniards were always defeated and he could never make a major military campaign against the people and the Comanches continued to make depredations almost everyday in northern New Mexico.
Split into simpler sentences: However, despite their efforts to defeat the Comanches, Spaniards troops were always defeated. In addition, he could never make a major military campaign against this people and the Comanches continued to make depredations almost everyday in northern New Mexico.