Complex sentence: At this time, the Incas found out that the Quechua was very widespread and decided that this was a tool to achieve the unification of the Empire; thus, the language began to spread across the Andes more enthusiastically.
Split into simpler sentences: At this time, the Incas found out that the Quechua was very widespread and decided that this was a tool to achieve the unification of the Empire. Thus the language began to spread across the Andes more enthusiastically.