Who are the four great calligraphers in China?

The four great calligraphers in China generally refer to the founders of Yan and Zhao Kaishu: Yan Zhenqing, Liu Gongquan, Ou Yangxun and Zhao Mengfu. Among them, Yan Zhenqing and Liu Gongquan are not controversial, while Ou Yangxun and Zhao Mengfu are controversial.

Four great calligraphers in the early Tang Dynasty: Ou Yangxun, Zhu Suiliang, Yu Shinan and Xue Ji.

Four Great Calligraphers in Song Dynasty: Su Dongpo, Huang Tingjian, Mi Fei and Cai Xiang. Calligraphers in the Eastern Jin Dynasty: Wang Xizhi, Mrs. Wei (female, teacher of Wang Xizhi) and Zhong You.