Barnes was born to the Ratwatte family, an old
Radala family hailing from the
Kingdom of Kandy, who were
courtiers of Sinhalese monarchs, including
Ratwatte,
Dissawa of Matale, a signatory to the 1815
Kandyan Convention. His father was Abeyratne Banda Ratwatte, Basnayake Nilame of the Maha Vishnu Devale and
shroff of the
Mercantile Bank of India in Kandy, and his mother was Thalgahagoda Lewke Punchi Kumarihamy, daughter of Thalgahagoda Rate Mahatmaya of
Matale. He had two brothers
Sir Cuda Ratwatte Adigar who served as
Mayor of
Kandy and
Harris Leuke Ratwatte who was former
Diyawadana Nilame of Sri Dalada Maligawa, Kandy. Educated at
Trinity College, Kandy, Ratwatte married Rosalind Mahawelatenne Kumarihamy, daughter of Mahawalatenne
Rate Mahatmaya of
Balangoda. Married under the
Binna marriage tradition of the
Kandyan law, Ratwatte became the executor of his wife's properties inherited from his father-in-law and also succeeded his father-in-law's government post of
Rate Mahatmaya of Balangoda. ==Career==