The earliest rocket launchers documented in imperial China launched fire arrows with launchers constructed of wood, basketry, and bamboo tubes. The rocket launchers divided the fire arrows with frames meant to keep the arrows separated, and were capable of firing multiple arrow rockets at once. Textual evidence and illustrations of various early rocket launchers are found in the 11th century Southern Song Dynasty text "Wujing Zongyao". The "Wujing Zongyao" describes a portable rocket arrow carrier consisting of a sling and a bamboo tube.