What was the original cause of the 30 years war in europe

What two things are being compared in this epic simile (the odysseus)

The persian empire finally fell to the armies of

Historians are concerned with the accuracy of their writings and readings but are also aware of the inability of authors to know every angle of every story biases, perspectives, beliefs, and a variety of other differences history being told by one person at a time no one being totally accurate, as hard as we try really need on this, and you^^