This secret mutual defense treaty was signed at a meeting arranged by Wilhelm II only four days beforehand. On the evening of Sunday 23 July 1905 the Kaiser arrived at Koivisto Sound from Viipuri Bay in his yacht, the Hohenzollern, which then dropped anchor near Tsar Nicholas' yacht, the Standart. Proof that the meeting took place is given by telegrams that they exchanged, dubbed the Willy–Nicky correspondence, made public in 1917 by the new revolutionary government in Russia.[2]