Complex sentence: The authorities of Austria-Hungary continually kept a close eye on the movement, but the reputation and prestige of the Sokol continued to grow; soon the Sokol members were known by most as the "Czech national army".
Split into simpler sentences: The authorities of Austria-Hungary kept a close watch on the movement, but the reputation and prestige of the Sokol continued to grow. Soon the Sokol members were known by most as the "Czech national army".