Bradbury wrote the refrain and the tune, but the original verses are by Anna Bartlett Warner. The DT makes the same misattribution found in this thread (which appears to be where most of its material came from). Warner wrote the poem (including the "even though I'm very ill" verse) in 1859 or 1860 and it appeared in a novel by her sister Susan. A couple years later, Bradbury wrote the refrain and tune and put it in one of his Sunday School hymnals. It did become very popular in foreign mission circles, and the tune is sometimes called CHINA in recognition of its reputation as the favorite Christian song of that country.

I'm trying to figure out exactly which verses Warner wrote (apparently two of the more commonly sung ones were subsequently added by one David Rutherford McGuire), but so far I haven't found a searchable online source for the novel.

I'm also trying to determine the year of Anna Warner's birth (1820 - 1824 - 1827?). Anybody have a documented idea?