Originally posted by: proteeti
Krishna, as Nand Nandan, was a Suta. (Since Nanda was the illegitimate eldest son of Shurasena through a Shudraa Daasi that is why Vasudev chose him to keep Krishna safe)
Radha was a Kshatriya, her father Brishabhanu was the King of Barsana. Nand was only the mukhiya of Gokul, and Vrindavan was somewhere in between where they took refuge so as to save themselves from Kans' demons.
Radha is called Rani, because she was the 'queen' of all the cowmaids of Barsana and Jarat. They were the ones to give her this epithet because she always took care of them and solved their problems like a real queen would. Her complement in this was Krishna who was called 'Rakhal-raja' or Cowherd King, because he was an integral part in Nand baba's administration from a very young age (and like to play 'war' with his friends)
Ayan Ghosh was also Kshatriya, living in a village called Jarat, and Radha also shifted to Jarat after her marriage. Only after that divorce thingy she came to Vrindavan and lived in a ottage by the river.