The Brooke letters, No. 4050 IV in the Oppenheimer Library, were written by Robert Brooke, Governor of St. Helena, to Earl Macartney, Governor of the Cape of Good Hope.

The letters show that Brooke felt feelings of warm friendship for Earl Macartney, to whom he acknowledged a debt of gratitude for the interest he had shown in his affairs.

As governors of neighbouring territories both men had problems in common and were able to assist each other. When Macartney was very short of specie at the Cape, Brooke was able to raise a private loan of 2500 to help him out of his difficulties.

Amongst the subjects discussed in the letters were the taking and future government of the Cape, the plan to attack Spanish South America, the progress of the war against the French, the convoying of East India Company ships and the seizure of neutral ships which are trading illegally.