It is mentioned in Wikipedia that David Parlett (The Penguin Book of Card Games, 1978) describes the Mexican game of Conquian as being the father to all rummy games.
Conquian rummy history is around 400 years old and was played in Spain and Mexico and later rummy reached America where people say that Conquian or Rummy Game also made its way to England and then back to Atlantic where it was called Rummy.
The history of Card Games goes century back as some say that rummy originated in Spain, some say it started in China but when it comes to India, children learn rummy from their parents of elder brothers/sisters who play a lot of rummy games with friends and family members.
Almost every family in India has a few deck of cards and they play card games including pretty often. And, it can be said that since rummy history comes from centuries, playing rummy has been an integral part of the entertainment for Indian families.
Now with the changing times and advent and penetration of Internet in India, more and more people are playing rummy online as its getting difficult to find time and meet frequently. Website like RummyCircle.com is attracting thousands of players every day who participate in rummy tournaments and play rummy24x7. It looks like that 10 years down the line, a new rummy history would be seen.
13 cards rummy blog, April 2010