It has been decades since the war. No one remembers it anymore, but a long time ago there were two kingdoms.  
The Changelings and the Glitterbugs, each ruled by a powerful leader. The war was awful, many deaths from both sides. It was heartbreaking. Both leaders saw this, so they came to a conclusion. They would stop the war for their people.  
But the war already took it’s tole, the kingdoms shaken from the attacks. The leaders decited to merge the two, creating a larger stronger whole.  
Now that had a king and a queen to rule them, that had more freedom to live and love, sharing resources and land. The king and queen soon had two daughters, thus showing the love and care for each other and the kingdom they created.
 
Oof, this took longer than expected. This is the next gen that my friend and I have created together. (I’ve got the bug ponies, she literally had everything else xD) I had a hard time making a background, might change it later.  
Headcannon, Soon after Chrysalis was thrown out, she got more land and started rebuilding her kingdom. Still sour from being kicked out of her own land, she waged war. The War lasted years and many lives were lost.  
They merged their kingdoms to create balance and stop the war. Chrysalis was in for it to get Celestia off her back at first, but then seeing her people able to eat without stealing sealed the deal. Being with Thorax, she started to soften and see how nice it could be. She now shares the duty with Thorax, but she is more strict and bossy than him. That doesn’t stop her from loving and caring for her two daughters, Changeing Peace and Shifting Harmony.
 
Shifting Harmony//  
Changing Peace//  
My little pony, Queen Chrysalis, King Thorax// Hasbro