Complex sentence: In just under two years, he had an army of some 6,000 men with 1,200 horses and 22 cannons, and, on January 17,1817, he set out with this force and began the crossing of the Andes.
Split into simpler sentences: In just under two years, he had an army of some 6,000 men, 1,200 horses and 22 cannons. On January 17,1817, he set out with this force and began the crossing of the Andes.