Complex sentence: To the south, Maj. Gen. Lafayette McLaws defended Crampton's Gap against Franklin, who was able to break through at Crampton's Gap, but the Confederates were able to hold Turner's and Fox's, if only precariously.
Split into simpler sentences: To the south, Maj. Gen. Lafayette McLaws defended Crampton's Gap against Franklin. Franklin was able to break through at Crampton's Gap, but the Confederates were able to hold Turner's and Fox's, if only precariously.