Explanation of environment (Persia)
When the Aryan people first migrated to the south to this vast land they found that it had very diverse natural climates conditions: such as warm lowlands, high cool mountains, rainy and humid in some parts and dry and sunny in the others- climates that accommodated all tastes and temperaments.
Since then the land they discovered this land, which they later called Eran, which means land of the Aryans, it has remained the same except some rivers changed direction in their flow, and some lakes dried up here and there. The mountains are the same from the time Zoroaster described the Azarbaijan mountains in the Avesta-the Zoroastrian scriptures over twenty-five centuries ago.
Eran, Iran, or Persia is enormous. About 1,650 square kilometers. It is fertile and lush for crops and greenery, but in some cases it is a mercilessly barren wasteland in other parts. In some part the soil is very dry and sandy like a desert and is unimaginably hot. (Like present day Iran!) There was drought in some places like you couldn't imagine and the soil was like baked clay! And it didn't matter how much water you poured on it.
In some places like the plains it is easy to build homes and it wasn't searing hot and they built houses and grew crops and they wore light clothing and they had lots of water systems! The ancient Persians were the first people to build their houses on the plains and they were also the first to learn how to search underground for water and to pump it out of the ground!
Next is The Roman Environment.