Final answer:
Nebuchadnezzar II expanded the Neo-Babylonian Empire mostly through military conquests, although they did focus on trade to bolster their economy. The empire was eventually conquered by Cyrus II of Persia, who also used military means to expand his territory.
Step-by-step explanation:
Nebuchadnezzar II expanded the Neo-Babylonian Empire primarily through military conquests. He extended the empire's control over Mesopotamia, Syria, and Judah, and even into the Arabian Peninsula. Notably, the Neo-Babylonians adopted some of the terror tactics of the Assyrians, which included deporting conquered enemies. However, they also emphasized trade, building new roads and canals to bolster long-distance commerce within their empire. Even while at war, trade routes remained open, showing a dimension of economic strategy alongside military expansion.
It is important to note that the end of the Neo-Babylonian Empire came with the rise of the Persians under Cyrus II, who conquered them after his victory over the Medes. Cyrus II leveraged military prowess and also assimilated the Medes into his forces, demonstrating another facet of ancient political expansions through military means rather than peaceful methods such as diplomacy or economic treaties.
An example of peaceful territorial acquisition in ancient city-states and empires would be arranged marriages, which were diplomatic alliances that could prevent military conflicts. However, in the context of the Neo-Babylonian Empire's expansion under Nebuchadnezzar II, military conquest was the primary method utilized.