[1] Maier "impressed" with charisma and enthusiasm, he had a high level of intelligence and scientifically sound training, was interested in art and politics and felt deeply connected to his home country.

Enthusiastic contact, coupled with a warm and open personality, made many friendships open to him across all social classes; however, he paid special attention to the care and upbringing of children and adolescents to independent and mature personalities; “dealing with them was uncomplicated and comradely..." According to contemporary witnesses, Maier was "a real buddy", "a happy person” and an “accurate soccer player.”[6] With the abolition of religious instruction by the Nazi regime, Maier also lost his job as a religion teacher at the Albertus Magnus School in Vienna Währing in 1938, but remained chaplain in the parish of Gersthof-St. Leopold in Vienna Währing, deepened his theological studies and received his doctorate in July 1942 (second doctorate - theology).

As early as May and June 1940, he contacted resistance groups around Jakob Kaiser, Felix Hurdes, Lois Weinberger, Adolf Schärf and Karl Seitz.

Out of his conviction, the Catholic faith and Austrian patriotism, he was a resistance fighter, who ultimately did not rule out militant means to suppress the Nazi regime.

The aim of the group was to bring about an end to the horrific regime by military defeat as soon as possible and to re-establish a free and democratic Austria.

[4][10] Maier advocated the following principle: "Every bomb that falls on armaments factories shortens the war and spares the civilian population.

[12] The exact drawings of the V-2 rocket, the production of the Tiger tank and Messerschmitt Bf 109 and others could be passed on via Maier's relationship with the Vienna city commander Heinrich "Rico" Stümpfl.

[16] In this regard, it is often stated that if the war against Nazi Germany had lasted longer, the first atomic bomb would have been used over Berlin or the industrial centers of Ludwigshafen am Rhein and Mannheim.

[17] Messner provided the first information about the mass murder of Jews from his Semperit plant near Auschwitz - a message the enormity of which amazed the Americans in Zurich.

However, the Maier-Messner-Caldonazzi resistance group's plan to bring an American transmitter of the Office of Strategic Services (OSS) from Liechtenstein to Austria failed.

To this end, a central committee or preparatory groups in the event of a collapse of the German Reich and a future independent state of Germany with a monarchical form of government were planned, which, in addition to Austria, should also include Bavaria and South Tyrol.

Helene Sokal and her later husband, the chemist Theodor Legradi, who had international connections to the communist resistance, among others, included the doctor Josef Wyhnal and the student Hermann Klepell.

In the summer of 1942, the resistance group was able to send a “memorandum” drawn up by Maier, Sokal and Legradi to the Allies (addressed to the British and Soviet Foreign Ministers), in which a current social analysis, military and economic information and the goals of a new Austria were presented.

[18] Leaflets were written in which Hitler was described as the "traitor of the German people" or "greatest curse-laden criminal of all time" and militarism as "the shame of our century".

Heinrich Maier was arrested on 28 March 1944 by the Gestapo in his parish in Vienna-Gersthof in the sacristy after the holy mass and taken to the prison in the former Hotel Métropole on Morzinplatz.

Regarding Maier's motives and thoughts regarding the transmission of information about arms, steel and aircraft factories to the Allies, the Volksgerichtshof stated: "The destruction of weapons manufacturers was intended to hit German armaments production and thereby shorten the war; in addition," independent Austria should "as a result, the industries necessary for peacebuilding are preserved intact and the settlements are spared."

The concentration camp guards tied Maier to the window cross of a barracks without clothes, they beat him until he passed out and his body looked more like a lump of meat, but he said nothing.

[24] Caldonazzi was beheaded at the Vienna Regional Court in January 1945 and Messner was gassed at the Mauthausen concentration camp in April 1945.

Chaplain Heinrich Maier was beheaded in the Vienna Regional Court on 22 March 1945 at 6.40 p.m.[25] His last words were "Long live Christ, the king!

Knowledge of Maier's resistance to the Nazi terror regime was largely suppressed in Austria after the Second World War, partly because he acted against the express instructions of his church superiors, partly because his political plans for a Habsburg constitutional monarchy in Central Europe (according to the plans of Winston Churchill) were sharply rejected by Joseph Stalin and the USSR.