Datis nuperrime (1956) is an encyclical of Pope Pius XII concerning the Soviet invasion of Hungary to suppress the Hungarian Revolution of 1956. This is a second encyclical protesting the bloody oppression of the Hungarian people. Pope Pius, as in his previous protests, does not mention the Soviet Union by name.

More information on the Wikipedia page [1].

An English version of the encyclical can be found here [2] and another version here [3].