When we go thru the “Ramcharitmanas” , then only understand the real cause of holy war and “Sita Haran” by “Ravana”.
“Ravana” was very intelligent, learned and wise, he gets to know or recognized the “Lord Ram" and "Goddess Sita". He wished to be killed by the arrow of “Lord Rama” and before abducting “Goddess Sita", he had offered “Pranam” to "Goddess Sita".
It is a very vast thing and cannot be discussed here.
The whole Romanized version of “Ramcharitmanas” can be downloaded from
gitapress.org
Here I pasting excerpt of “Doha or Choupai” and meaning of it is below, which illustrate this,