Out of the many stories that come out as reasons for the name of my city, the following seemed to be interesting for Madras.
1. It is believed that the original Portuguese name is Madre de Sois, named after a Portuguese high authority who was one among the early settlers in 1500.
2. The British seemed to have obtained the land for building Fort St George from a fisherman named Madras, on whose honor they named the city that developed around the fort.
The reason for Chennai seems to be as follows.
1. Named after Chennappa Naayakkar, who sold the land to the British.
2. Chennai was loosely the name used to represent the old towns of Triplicane and Mylapore.
Whatever it may be, the truth has been established in literature that Chennai is a Telugu word and Madras is a Portuguese derived word. But the current politicians are keen to establish that Chennai is the Tamil word and Madras as the English word. Ok back to the old story. The town that grew around the fort, north of the Cooum River, was popularly called Madrasa pattinam. (Pattinam means seashore town in Tamil). And the region to the south of the Cooum River (Triplicane and Mylapore) was called Chennai. But soon these two were linked by roads and bridges and it virtually became one town.
The British preferred to use the name Madras and still there were people who preferred the name Chennai. This same heritage has lasted till today and they have been fighting for changing the name with foolish arguments. My person opinion is in favor of Madras. It has been a long established name and they could have at least left it for this simple reason.