The Neo-Assyrian Period, which lasted from approximately 911 to 609 BCE, marked the height of the Assyrian Empire's power and territorial expansion. This era is characterized by military conquests, advanced administrative systems, and monumental architecture, including the grand palaces of Nineveh and Ashur. During this time, the Assyrians developed a sophisticated culture, with significant contributions to art, literature, and science. The empire's rulers, such as Ashurbanipal, are known for their extensive libraries and patronage of the arts, which helped preserve much of Mesopotamian knowledge for future generations.