What Were The Causes Of Nationalization Of Banks?

This is rather a general question.  To which country do you refer?

Nationalization of banks can take place for many reasons.  The most obvious would be that the central government, of any country, would want direct control of the bank itself.  (This was an enormous debate in the founding of the United States and involved heated discussions.)  Such a central government could then determine and enforce business policy (policy being not law, but merely a set of rules governing a particular business; in this case, banks).

Another reason would be to have guaranteed uniform standards in all branch locations.  Suppose you have four or five bank franchises spread throughout a nation.  All of these banks, while likely following federal law, will have their own unique ways of carrying out business, right or wrong.  With nationalized banks, there is one way of doing business, and one way only (in theory): The central government's way.