Most of the documents in this series, previously located at ML A78-4, were purchased in 1884 from Lord Brabourne by Sir Saul Samuel, the Agent-General for New South Wales. They were transferred to the Mitchell Library in 1910 and were part of the accession which became known as the Brabourne collection. Document 1 was acquired for the Mitchell Library on 7 May 1940 and was placed first at ML Ab60 and then at ML A80-4. It is now not possible to reconstruct Banks' original arrangement, the series has therefore been arranged chronologically.
William Bligh chose Nathaniel Portlock to command the brig Assistant, the tender to HMS Providence on the second breadfruit voyage. The small expedition left England in August 1791 and returned in August 1793 after successfully completing the voyage to transport breadfruit and other plants to the West Indies. Bligh was plagued by ill health during most of the voyage and Portlock, as a consequence, carried increased responsibility. Together Bligh and Portlock negotiated and charted the straits between Australia and New Guinea.