Complex sentence: In the 1860s students from Great Britain began to cheer and chant in unison for their favorite athletes at athletic events soon having the gesture of support cross over seas and begin the roots of cheerleading to sprout in the United States.
Split into simpler sentences: In the 1860s students from Great Britain began to cheer and chant in unison for their favorite athletes at sporting events. Soon having that gesture of support cross over seas and begin the roots of cheerleading to sprout in the United States.