An Ambassador is an honest man, sent to lie abroad for the good of his country.

[Legatus est vir bonus, peregrè missus ad mentiendum Reipublicae causâ.]

Henry Wotton (1568-1639) English author, diplomat, politician

Reliquiae Wottonainae (1651)
    (Source)

Wotton wrote in an apology to Velserus in 1612, that during his travel through Augsburg in 1604, "This merry definition of an ambassador I had chanced to set down at my friend's, Mr. Christopher Fleckamore, in his Album". It seems to have been intended as a pun when translated to English.Sometimes translated as "An ambassador is an honest gentleman sent to lie abroad for the good of his country."