During the 19th century, when the British went around to recruit Tamils of India to work in many parts of their empire, they have a problem recording down the names of the workers because all of them have only one given name. For example, from just one village, they may get 30 Arumugam which would very difficult to keep track. So what they did was they added the S/O followed by their father's names and from then onwards, the descendants of the imported labourers from India have followed the convention when naming their children. With the emphasis on BM, the S/O changed to A/L.