Are there historical examples of a nation splitting into 2 or more nations with very little or no aggression?

by ProfessorPaulKrugman
OtherReality

[This article on missing countries] (http://geography.about.com/od/politicalgeography/a/missingcountry.htm)

Seems like splitting and reuniting has been quite a common process for countries.

Thinking of England and Scotland and Spain and Catalonia in the future. ... and I guess the USSR break up, which created a bunch of countries.