Complex sentence: Colonel Simón Bolívar then launched a major offensive against the Spanish forces who were on the east bank of the Magdalena River and quickly achieved resounding victories that led him to undertake a journey to liberate the Valley of Cúcuta held by the command of royalist Colonel Ramon Correa.
Split into simpler sentences: Colonel Simón Bolívar then launched a major offensive against the Spanish forces who were on the east bank of the Magdalena River and quickly achieved resounding victories. These led him to undertake a journey to liberate the Valley of Cúcuta held by the command of royalist Colonel Ramon Correa.