What Country Entered World War I On May 23, 1915?

Italy joined World War I on May 23, 1915. The Italian Prime Minister Antonio Salandra gave his asset for his country to join the world war by giving his declaration of support to the Allies. Italy had followed a 'policy of neutrality' when the war first started on August 2, 1914. However the government was influenced to join the war and partner the Allies in May 1915.                   
  
Italy was the part of Trial Alliance, a military alliance comprising of Germany, Austria-Hungary, which lasted from 1882 till World War I in 1914.   The decision of Italy to join the war was done purely by the enticement of territorial rewards offered by the Allies. The secret treaty of London was a major influence under which Italy was promised major territorial gains at the end of the war at Hungary and Austria's expense.