Was it painted by Adomas Varnas? Is he the one in question?
Based on Eugeniusz Romer, The History of Poles in Lithuania (Memoirs from 1871-1939), ed. Maria Rodowicz, Multiart, Warszawa 2014
After the May Coup of 1926, we wanted to inform Marshal Józef Piłsudski about the situation of the Polish minority in Lithuania, as we were cut off from direct contacts with Poland. The pretext was the portrait of Bronisław Piłsudski, the Marshal’s brother, which we found and purchased. They sent me to Warszawa to give the portrait to Józef Piłsudski. The Marshal received me very kindly and kept me for nearly an hour, expressing his thoughts on Lithuanian issues, but not allowing me to speak. Therefore, I could not present to the Marshal my expose on our situation in the Kaunas region of Lithuania. As a farewell, he instructed me to go to the Deputy Prime Minister Professor Kazimierz Bartel. One day, a few years later in Lviv, where my son Red studied, I met Professor Bartel. He remembered me perfectly, as well as the instructions of the Marshal who told him at that time in Warszawa to receive Romer and arrange everything he would ask of him, “because he was a very wise man.” Apparently silence can sometimes be considered an evidence of wisdom.
I wrote it in 1938.