On 21 March, Patton ordered his XII Corps to prepare for an assault over the Rhine on the following night, one day before Montgomery's scheduled crossing. While this was short notice, it did not catch the XII Corps completely unaware. As soon as Patton had received the orders on the 19th to make a crossing, he had begun sending assault boats, bridging equipment and other supplies forward from depots in Lorraine where they had been stockpiled since autumn in the expectation of just such an opportunity.