First, Shaolin Kungfu was basically Luohan Boxing, the origin of the various routines of Shaolin Kungfu. Shaolin Monks created the Xinyi (Heart-and-Mind) Boxing, mimicking the actions of animals and human labour to defend themselves against wild animals. But this was still far from being an integral system of Shaolin Boxing routines.
During the Song Dynasty, Fu Ju, abbot of Shaolin Temple, invited experts from 18 wushu schools to exchange and teach each other skills at Shaolin. They remained for 3 years and edited the Shaolin Boxing Manual which described 280 routines.
During the Jin and Yuan Dynasties, monk Jue Yuan travelled to Luoyang and Lanzhou where he met experts Bai Yufeng and Li Sou, and with them to Shaolin for further exchange of wushu skills. Subsequently, more than 70 routines of Shaolin Boxing were created on the basic 18 routines of Luohan Boxing, which developed further into 173. Jue Yuan also created the Leopard, Snake, Crane, Tiger and Dragon Boxings and developed the Art of Attack.
During the Qing Dynasty, the government but a ban on the practice of weapons which caused many monks of Shaolin to leave and roam the country. When they returned, these monks brought back what they learned from other schools. At night, the monks take out their weapons and start practising all they had learned. By the end of the Qing Dynasty there were already several hundred types of Shaolin Boxing in current use. Though some have been lost since, more that 100 sets of sparring have survived such as Pao (cannon), Yuan (monkey) Xinyi (heart-and-mind), Luohan, Xianhong, and much, MUCH more other boxings.