her face "makes a strange foreign impression." By about 1910, myriad imitators had arisen. Critics began to opine that the success and dazzling features of the popular Mata Hari were due to cheap exhibitionism and lacked artistic merit. Although she continued to schedule important social events throughout Europe, she was disdained by serious cultural institutions as a dancer who did not know how to dance. Mata Hari's career went into decline after 1912. On 13 March 1915, she performed in the last show of her career. She had begun her career relatively late as a dancer and had started putting on weight. However, by this time, she had become a successful courtesan, known more for her sensuality and eroticism than for her classical beauty. She had relationships with high-ranking military officers, politicians, and others in influential positions in many countries. Her relationships and liaisons with powerful men frequently took her across international borders. Before World War I, she was generally viewed as an artist and a free-spirited bohemian, but as war approached, she began to be seen by some as a wanton and promiscuous woman, and perhaps a dangerous seductress. Espionage During World War I, the Netherlands remained neutral. As a Dutch subject, Zelle was thus able to cross national borders freely. To avoid the battlefields, she traveled between France and the Netherlands via Spain and Britain, and her movements inevitably attracted attention. During the war, Zelle was involved in what was described as a very intense romantic-sexual relationship with Captain Vadim Maslov, a 23-year-old Russian pilot serving with the French, whom she called the love of her life. Maslov was part of the 50,000-strong Russian Expeditionary Force sent to the Western Front in the spring of 1916. In the summer of 1916, Maslov was shot down and badly wounded during a dogfight with the Germans, losing his sight in his left eye, which led Zelle to ask for permission to visit her wounded lover at the hospital where he was staying near the front. As a citizen of a neutral country, Zelle would not normally be allowed near the front. Zelle was met by agents from the Deuxième Bureau who told her that she would be allowed to see Maslov if she agreed to spy for France. Before the war, Zelle had performed as Mata Hari several times before the Crown Prince Wilhelm, eldest son of Kaiser Wilhelm II