Russia had previously obtained recognition from the Ottoman Empire of the Tsar's role as special guardian of the Orthodox Christians in Moldavia and Wallachia. Now Russia used the Sultan's failure to resolve the issue of the protection of the Christian sites in the Holy Land as a pretext for Russian occupation of these Danubian provinces. Nicholas believed that the European powers, especially Austria, would not object strongly to the annexation of a few neighbouring Ottoman provinces, especially considering that Russia had assisted Austria's efforts in suppressing the Hungarian Revolution in 1849.
Who was given the special role of guardian over the Orthodox Christians in Moldavia and Wallachia?
{'text': 'Russia', 'answer_start': 0}