Cai Gao
Cai Gao (1788–1818), also known as Tsae A-ko and by various other names, was the first Protestant convert in mainland China. He has also been called the first Western-style type-cutter and letterpress printer.
The real name of China's first Protestant convert is uncertain, although his surname was "almost certainly" . Like those of his family members, his name was recorded only in the missionaries' English romanizations, which include "Tsae-a-ko","A-fo", and "A-no". Over the next two centuries, this was variously modernized as "Tsae A-ko","A-Ko", "Ako", and "Ko". It has become generally accepted that these rendered the given names and , which would be Cai Gao or Yagao in pinyin. Su and Ying, however, believe the original name to have been , which would be Cai Ke in pinyin. Smith also gives the Cantonese form as Choi A-ko.
Cai Gao's father was a Cantonese merchant at Macao whose legal wife had borne him no children; Gao's mother was his second concubine. He had an elder brother (born c. 1782) whose name variously appears as "Low Hëen", "Low-hëen","A-hëen", and "A-këen". He had another brother "A-yun" or "Ayun", who was "a child", younger than Low-hëen and whom Morrison "wish[ed] to educate". Though frequently taken as Gao's younger brother,A-yun appears as his "elder brother" in the Mission Society's 1819 report. Morrison's journals mention an "A-Sam" who was distinct from A-yun and, as "a lad", distinct from his older tutor and companion Yong Sam-tak. McNeur, Gu, and Zetzsche do not mention A-yun as one of Gao's brothers but do say that "A-sam" was his younger brother.
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