January 17, 1944 May 18, 1944Battle of Monte Cassino / PeriodcassinoonlineSubsequent Allied assaults up the mountain achieved little despite heavy casualties. Polish troops finally captured Monte Cassino on May 18, 1944, five months into the bloody campaign and four months after the monastery was leveled.The Destruction of Monte Cassino | New Orleansnationalww2museum : war : articles : destruction-of-monte-cass...cassinoonline bet bwin login