At age 36.
Ying Zheng announced to the world that his third child and second son would be co-emperor with him while he is still alive. The people although surprised did not care much.
Age 37
Ying Zheng attempted to conquer the lower Nile regions of Egypt and Abyssinia but unfortunately failed. Ying Zheng felt he had already gone past his prime.
Age 38.
Ying Zheng solidified his rule strengthened his foundations and grew his roots deeper. Man Tian again tried to conquer the lower Nile regions but failed once again.
Age 39.
Ying Zheng seeing that the lower Nile regions was not that successful moved west to the Libyan region and conquered most of North Africa in one stroke.
Age 40.