Born in Galați,[1] he joined, while still in high school,[1] the Legion of the Archangel Michael (later also known as the Iron Guard), an ultra-nationalist, Fascist, and antisemitic political movement led by Corneliu Zelea Codreanu.
A prominent activist in his native Covurlui County,[1] jailed more than once for his activism, he was awarded the White Cross (Crucea Albă), the movement's highest distinction, and eventually became Codreanu's lieutenant.
[2] Stelescu, together with Codreanu, General Gheorghe Cantacuzino-Grănicerul, Nichifor Crainic, and others, was tried for criminal conspiracy following the assassination of Prime Minister Ion G. Duca — all were acquitted by a jury comprising Legion sympathisers.
[4] As a consequence, in 1935, he created his own political movement, originally called the White Eagles (Vulturii Albi),[5] but later known as the Crusade of Romanianism (Cruciada Românismului), and began publishing a weekly magazine of the same name, in which he fiercely attacked Codreanu and the Legion.
However, the Legionnaires bitterly hated Stelescu as an apostate, and that the details of the plot to assassinate Codreanu are hardly credible; at that time, the King would probably have supported anything that promised to reduce the Legion's growth and influence.
Faced with lack of appeal, the group adhered to the Constitutional Front, a nationalist electoral alliance formed around the National Liberal Party-Brătianu and Alexandru Averescu's People's Party (it also included for some time the short-lived Citizen Bloc, presided by Grigore Forțu).
While recovering, he was found by the Decemviri (the "Ten Men"), an Iron Guard death squad led by Ion Caratănase and probably created in 1935 in Târgu Mureș (during a youth congress tolerated by the Gheorghe Tătărescu executive).