The nice list of free online data sources Data sources online does not mention any data from ratings agencies.
Are historical time series available for sovereign credit ratings (other than as proprietary datasets)?
I realise that the ratings agencies probably would claim their ratings of sovereign debt as proprietary data, yet due to the way this information is disseminated and used it appears to be in the public interest for it to be available freely, and it also appears possible to recover some parts of the time series from the public domain. However, I cannot locate any free sources.
The Guardian made available a snapshot in July 2010, but I would like to analyse how the ratings have changed over time. I would be happy with a subset where nontrivial changes have taken place: for instance, a series for just Greece and Japan would be of interest. I can of course deduce some of the few unchanging series myself.