Gothic former Dominican Church, with its unique collection of medieval manuscripts, rare Renaissance books and ancient Roman artifacts. Formal attack On 26 August, Werder decided to go ahead with formal siege operations against the fortress. On 27 August, he sent a report to royal headquarters on his intention to open the first parallel on the night of 29–30 August. The Germans had carried out preparations for the formal siege even as the bombardment proceeded. These included entrenching tool depots at Bischheim and Suffelweyersheim and the platforms, artillery parks and materiel of the siege artillery at Kork, Kehl, Neumühl and Vendenheim. By 24 August, the infantry had trained in the building of trenches by engineer officers. To reconnoiter the fortress more closely and cover the main approach, the German lines of outposts moved forward on 27 August after dark between Königshoffen and the Aar to within 300 meters of the glacis. There was no French resistance. On the morning of 28 August, the lines of outposts were withdrawn back to their previous positions after pioneers had constructed sufficient cover in the rain. At 1000 on 28 August, the French garrison opened up with rifle and artillery fire. At 1200, two French companies sortied out from the covered way near the Stone Gate. A company of the Schneidemühl Landwehr battalion repulsed the attack with some support and skirmished with the French until dark. French wall pieces and infantry fired from the No. 44 lunette against the Prussian position at Kronenburg. A French detachment of several hundred men momentarily captured the outermost Prussian trenches but was then thrown back by the Prussian infantry's file-fire. Two Landwehr battalions from the Guard Landwehr Division occupied this line of trenches in the evening. On the night of 28–29 August, the line of trenches was extended to cover the entire attack sector and communications were established along the line. Werder ordered the island of Wacken taken to cover the left flank. A company of the Konitz Landwehr Battalion crossed a pontoon bridge that had been erected by pioneers and threw out the French outposts on the island. A French company from Jars island attempted a counterattack on the morning of 29 August, but was defeated by the Landwehr company with the help of some troops of the Deutsch-Krone Landwehr Battalion. The Landwehr company sent some skirmishers to pursue the French to Jars island but these were withdrawn