After two months of siege Pappenheim finally convinced Tilly, who had brought reinforcements, to storm the city on 20 May with 40,000 men under the personal command of Pappenheim. The Magdeburg citizens had hoped in vain for a Swedish relief attack. On the last day of the siege, the councillors decided it was time to sue for peace, but word of their decision did not reach Tilly in time. In the early morning of 20 May, the attack began with heavy artillery fire. Soon afterward, Pappenheim and Tilly launched infantry attacks. The fortifications were breached and Imperial forces were able to overpower the defenders to open the Kröcken Gate, which allowed the entire army to enter the city to plunder it. The defence of the city was further weakened and demoralised when commander Dietrich von Falkenberg was shot dead by Catholic Imperial troops. The Sack of Magdeburg is considered the worst massacre of the Thirty Years' War resulting in the deaths of around 20,000. Magdeburg, then one of the largest cities in Germany, having well over 25,000 inhabitants in 1630, did not recover its importance until well into the 18th century.