Monarchies originated for a newly founded society to function with a leader at the top. They originated at around 3000 BCE most likely in Egypt or Sumer and kings and queens held a divine status there and in many countries after them.
It is difficult to change a type of government in general because that requires changing many parts of how that particular society works. And since the monarch class holds most or all power in a given state it is very hard to convince them that they should stop ruling. This is why violent revolutions against absolute monarch rule happened many times in history.
In the 1800s they used steel plows and other new forms of technology. The Steel Plow was used for farming to break up tough soil without soil getting stuck to it.
