Reflecting the international sensitivities involved, negotiations progressed outside the "usual" diplomatic channels.[5] To confirm his approval for the proposal, Cavour sent his diplomat, Costantino Nigra, to Paris, where Nigra made contact with another friend and confidant of the emperor (and another physician) called Henri Conneau.[5] On 9 May 1858 Conneau was able to confirm to Nigra that the alliance proposal had the full support of the emperor himself.