Tsae A-Ko

An engraving of George Chinnery's lost Robert Morrison Translating the Bible . Morrison is assisted by Li Shigong (left) and Chen Laoyi (right).

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.

Name The real name of China's first Protestant convert is uncertain, although his surname was "almost certainly" . which include , and . Over the next two centuries, this was variously modernized as , , "Ako", which would be and . who was "a child", younger than Low-hëen and whom Morrison "wish[ed] to educate". Though frequently taken as Gao's younger brother, appears as his "elder brother" in the Mission Society's 1819 report. Morrison's journals mention an who was distinct from 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.

The use of lou⁵ (, p lǎo, "old") and aa³ (then , p yà or yǎ, but now , ā, "dear ~, dear little ~") reflects the standard practice of Cantonese nicknames. Morrison notes that these were generally used without "Tsae, being the sacred or family name". As the elder member of the family, "Low-hëen" received the affectionate honorific "low-" and the others the diminutive "a-". While it is possible "Low-hëen" and "A-hëen" were different members of the family, they are not distinguished as such by Morrison.

Life Cai Gao was born in 1788. He and his brothers were given a good Chinese education, although Gao's poor health caused him to fall behind his brother Low-hëen. The father died when Gao was sixteen. Upon the ruin of their family, their father's debts were so large that Gao's brother Low-hëen was suddenly arrested and imprisoned over a decade later for the unpaid amount.

In March 1808, Gao—then 20 and, with additional assistance from William Milne, wrote the first major Chinese–English, English–Chinese dictionary from 1815 to 1823. Low-hëen was already Morrison's tutor and companion,

In January 1817, officers from Guangdong raided the East India Company's printing offices on Macao, prompting all Morrison's Chinese associates to flee. Gao and two others snuck onto a ship bound for British Malacca. Morrison paid the stow-aways' fare, giving $6 and two boxes of tea to their families in China. He further gave Gao an interest-free $200 loan to start a business to provide for his livelihood while abroad. After he arrived, he began writing books for the London Missionary Society's station. He was probably also responsible for the hand-cut Chinese type used by the station's printing press. With the station's printer Liang Fa, who had become the second baptized mainland Chinese in 1816, he attended William Milne's open Sunday services and private lessons each Tuesday evening at 8. Milne found both "sincere, tho very imperfect, Christians".

Cai Gao returned to China after six months abroad. On 10 October 1818, Morrison wrote to the London Missionary Society to say that his convert was "suffering from a serious lung disease and I fear this illness is on the verge of ending his life". He died before the end of the month This date is also given by an article in the 1887 Chinese Recorder. of pulmonary consumption. His brother Low-hëen did not return to Morrison's employment after the raid but he unexpectedly wrote to Morrison in Macao in 1822 requesting baptism. No extant record records it, but they remained close and Low-hëen continued to attend Morrison's gatherings and services until 1827. Another of Gao's brothers, A-yun, began working for the LMS missionary John Slater while in Malacca in 1818 but returned to China by November 1819, when officers hunted him and Morrison's other Chinese associates for their involvement with Liang Fa's attempted publication of a Christian tract for distribution in his native village. Morrison hid him in his locked bedroom until he could escape under cover of darkness. He then accompanied Morrison to Malacca in early 1823 to deal with the problems caused by Milne's death, after which his fate is unrecorded.

Legacy A Protestant chapel in Macau bore his name.