Why did ancient Roman civilization last as long as it did?

The Roman Empire was long-lived for many reasons, some of which being new laws and engineering, military potency, and social legislation to combat political fragmentation along with exceptional leaders.

The Roman Empire was long lived as long as it did for

First of all ,1000 years is how much years ancient Roman civilization lasted.

So the reasons are

"new laws and engineering, military potency, and social legislation to combat political fragmentation along with exceptional leaders"

Acording to /www.ancientdigger.com/

"The Roman army was the largest and meanest fighting force in the ancient world. One of the main reasons Rome became so powerful was because of the strength of its army. It conquered a vast empire that stretched from Britain all the way to the Middle East. The army was very advanced for its time."

Acording to : bbc uk

So this is my answer hope it helps !

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.