Many people believed that the sun god enjoyed human
sacrifice
The south was technically fighting a defensive war, they had more time to prepare so really any of these answers could be right, but id have to go with they had either more money or more effective military commanders
One of the most determining factor is demand for foreign luxury goods increased in Afro-Eurasia. Due to this demand, many of the nobilities started to collected goods from Asia because it seem exotic for the collection. Their textile also require silk which could be easily found in chinese, persia, and indian regions which contributed to an increase in demand for textiles.
