The reference is to two of Cicero's letters to Trebatius, a Roman lawyer residing in Britain. In the first, Cicero gives a friendly caution —'See that you, who know so well how to manage securities for others, secure yourself against the wiles of the British charioteers (essedae)' — just as we might caution a friend travelling in Africa against the assegais of the Zulus. In another letter he rallies Trebatius on the recognition of his talents by Caesar, in the words quoted (1. 5) by Swift: 'Think yourself lucky to find yourself where you haye got the reputation of some wisdom.'