Question

The persian ruler __________ established the largest empire known.

Answer 1

The persian ruler, Darius established the largest empire known. Until his time at least.
He was considered as the Greatest persian ruler. During his reign, the persian empire reach its largest extent, surpassing cyrus'

hope this helps

Answer 2

Answer:    Darius the Great

Explanation:  Also known as Darius I, he was the Persian king who created the largest empire of the ancient world, and according to some scientists, he had established the largest empire ever. He also succumbed to the Greeks after the Ionic rebellion, even reached Macedonia and subdued. In addition, his empire extended to India, most of Western Asia, Central Asia, the mentioned Balkans with Greek territories, much of the Black Sea coast, the North Caucasus, Northeast Africa, and the Sudanese coast.

Moreover, his contribution was the improvement of the administration. He divided the empire into provinces, and since there were many different peoples with their customs and religions within the empire, in each province, he appointed a local administrator to resolve local issues. He also promoted administrative work at the empire level by introducing Aramaic as the only official language, then centralizing the supreme authority and thus facilitating work. He built and improved the existing road network, facilitated trade, standardized the measures.