分久必合，合久必分
fēnjiǔbìhé,héjiǔbìfēn
ㄈㄣ ㄐㄧㄡˇ ㄅㄧˋ ㄏㄜˊ , ㄏㄜˊ ㄐㄧㄡˇ ㄅㄧˋ ㄈㄣ
- 1(lit.) that which is long divided must unify, and that which is long unified must divide (proverb, from Romance of the Three Kingdoms 三國演義|三国演义[San1 guo2 Yan3 yi4])
- 2(fig.) things are constantly changing