[SixSigma]

http://chronicle.nytlabs.com/?keyword=istanbul.constantinopl...

This was by edict

"The international name Constantinople also remained in use until the Turkish Postal Service Law of March 28, 1930, according to which all foreign countries were asked to solely use the name Istanbul also in their languages and their postal service networks."

[DanBC]

Compare that to Myanmar / Burma, who also ask people to use the Myanmar form. Since it's not a democratic government there is some resistance to the new name.

http://chronicle.nytlabs.com/?keyword=burma.myanmar

[stan_rogers]

There was resistance to Istanbul as well; the hit song Istanbul (Not Constantinople) dates from 1953.

[paul_f]

Surely I'm not the only one who instantly thought of this:

https://www.youtube.com/watch?v=dsRuurcTTSk