The ancient Mesopotamian civilization known for their military prowess and conquests is the Assyrians. The Assyrian Empire emerged in the 14th century BCE and reached its peak during the 9th to 7th centuries BCE. They were a Semitic-speaking people who inhabited the region of Assyria in present-day northern Iraq.

Key Points:
1. Military Organization and Strategy:
- The Assyrians were renowned for their highly organized and efficient military. They had a standing army composed of professional soldiers who were well-trained and well-equipped.
- The army was divided into different specialized units such as infantry, cavalry, charioteers, and archers. They also had siege engineers and a navy.
- The Assyrians developed advanced military tactics and strategies, including the use of combined arms and the construction of fortified camps during campaigns.
- They also employed psychological warfare by instilling fear in their enemies through brutal tactics and the use of terror.

2. Conquests and Expansion:
- The Assyrians were one of the most successful ancient civilizations in terms of conquests and territorial expansion. They established a vast empire that covered present-day Iraq, Syria, Lebanon, and parts of Iran and Turkey.
- Under kings such as Tiglath-Pileser III, Sargon II, and Ashurbanipal, the Assyrians conducted numerous military campaigns and conquered various neighboring kingdoms and empires.
- They used a combination of military force, diplomacy, and political alliances to expand their empire. Their conquests brought them great wealth, resources, and tribute from subjugated regions.

3. Military Innovations and Technology:
- The Assyrians were innovators in military technology. They developed advanced weapons such as the composite bow, iron weapons, and siege engines like battering rams and siege towers.
- They were also skilled in siege warfare and were able to conquer heavily fortified cities using tactics like mining, breaching walls, and building ramps.
- The Assyrians were pioneers in the use of horse-drawn chariots in warfare, which gave them a significant advantage on the battlefield.

Conclusion:
The Assyrians were a formidable military power in ancient Mesopotamia. Their well-organized army, advanced military tactics, and relentless conquests allowed them to establish one of the largest empires of the time. Their military prowess left a lasting impact on the region and influenced subsequent civilizations in terms of military organization and strategy.