[2] Mościcki was the President of Poland when Germany invaded the country on 1 September 1939 and started World War II.

After completing school in Warsaw, he studied chemistry at the Riga Polytechnicum, where he joined the Polish underground leftist organization, Proletariat.

[3] Upon graduating, he returned to Warsaw but was threatened by the Tsarist secret police with life imprisonment in Siberia and was forced to emigrate in 1892 to London.

As a result of the agreement, Rydz-Śmigły would become the de facto leader of Poland until the outbreak of the war, and Mościcki remained influential by continuing in office as president.

Mościcki remained president until September 1939, when he was interned in Romania[7] after the German invasion of Poland and was forced by France to resign his office.

The relevant Polish authorities agreed that a funeral was to be held in Warsaw and be completely private, without any state ceremonies.

However, the authorities of the Canton of Geneva in Switzerland withdrew their agreement for political reasons after protests related to Solidarity from emigrants.

[9] The mortal remains of his daughter Helena and her husband Aleksander Bobkowski were also moved in September 1993 to the Mościcki family tomb at the Powązki Cemetery in Warsaw