The plan for Operation Diadem was that U.S. II Corps, on the left, would attack up the coast along the line of Route 7 towards Rome. The French Corps to their right would attack from the bridgehead across the Garigliano, originally created by British X Corps in the first battle in January, into the Aurunci Mountains, which formed a barrier between the coastal plain and the Liri Valley. British XIII Corps in the centre right of the front would attack along the Liri valley. On the right, Polish II Corps (3rd and 5th Divisions), commanded by Lieutenant General Władysław Anders, had relieved the British 78th Division in the mountains behind Cassino on 24 April and would attempt the task that had defeated the 4th Indian Division in February: isolate the monastery and push round behind it into the Liri valley to link with XIII Corps' thrust and pinch out the Cassino position. It was hoped that, being a much larger force than their 4th Indian Division predecessors, they would be able to saturate the German defences, which would, as a result, be unable to give supporting fire to each other's positions. Improved weather, ground conditions, and supply would also be important factors. Once again, the pinching manoeuvres by the Polish and British Corps were key to the overall success. The Canadian I Corps would be held in reserve, ready to exploit the expected breakthrough. Once the German 10th Army had been defeated, the U.S. VI Corps would break out of the Anzio beachhead to cut off the retreating Germans in the Alban Hills.
The plan for Operation Diadem was that US II Corps on the left would attack up the coast along the line of Route 7 towards Rome The French Corps to their right would attack from the bridgehead across the Garigliano originally created by British X Corps in the first battle in January into the Aurunci Mountains which formed a barrier between the coastal plain and the Liri Valley British XIII Corps in the centre right of the front would attack along the Liri valley On the right Polish II Corps (3rd and 5th Divisions) commanded by Lieutenant General Władysław Anders had relieved the British 78th Division in the mountains behind Cassino on 24 April and would attempt the task that had defeated the 4th Indian Division in February isolate the monastery and push round behind it into the Liri valley to link with XIII Corps' thrust and pinch out the Cassino position It was hoped that being a much larger force than their 4th Indian Division predecessors they would be able to saturate the German defences which would as a result be unable to give supporting fire to each other's positions Improved weather ground conditions and supply would also be important factors Once again the pinching manoeuvres by the Polish and British Corps were key to the overall success The Canadian I Corps would be held in reserve ready to exploit the expected breakthrough Once the German 10th Army had been defeated the US VI Corps would break out of the Anzio beachhead to cut off the retreating Germans in the Alban Hills