Clue: Pre-Rainbow Nation province in six-colour rainbow condition? (6,4,5)
Answer: ORANGE FREE STATE
Explanation: Definition: Pre-Rainbow Nation province
Richard of York gained battles in vain: orange is one of the seven colours in the traditional rainbow. The Orange Free State was originally an independent republic; after the Boer Wars, it became a British colony, then was incorporated as a province of the Union of South Africa, which, post-apartheid, is sometimes known as the Rainbow Nation (a term coined by Archbishop Tutu).