Many historians consider it unlikely that he ordered the city torched. Magdeburg was a strategically vital city of the Elbe and was needed as a resupply center for the looming fight against the Swedes. Although extremely opposed to the Reformation movement, Tilly was an experienced commander and would have recognized the strategic importance of the city. Additionally, he sent a proposal of surrender to Magdeburg days before the final assault, after the capture of the Toll redoubt. However, the city's mayor rejected the offer, expecting a Swedish relief force to arrive soon. When the slaughter began, and no escape was possible, the children of the city were formed in procession and marched across the marketplace singing Luther's hymn: "Lord keep us steadfast in thy Word, Curb Pope and Turk who by the sword, would wrest the kingdom from thy Son, and set at naught all he hath done." The children were slain without mercy, but whether by order from Tilly or not remains debated in some quarters. Tilly afterwards reportedly wrote to the Emperor,