I just finished Jasienica's HE COMMONWEALH OF BOTH NATIONS II: CALAMITY OF THE REALM, 1992 English version. He more I read about this historian (plus the comments made above), the more someone should make a movie about his life!!! He lived a jam-packed life, did a lot of things and died young.
He was a journalist first and foremost. This is how he made his living. He was a contributor and editor of newspapers, magazines, weeklies, etc. he also worked for PAX Association and became director of the Polish Caritas charity.
PAWEL JASIENICA WAS NOT HIS REAL NAME. it was his "pen name". his real name was Leon Lech Beynar. How did this happen? He was a soldier. He was in the Polish army, captured by the Wehrmacht but managed to escape. He joined the Armia Krajowa and was also an editor of an underground newspaper. Attempting to dislodge the Nazis from Wilno his outfit was captured by the Soviets. He was given a choice to join the Soviets or spend vacation in Siberia. Instead, he escaped and rejoined the AK. He then joined the anti-Soviet campaign and was wounded in August, 1945 (remember the was "ended" in May, 1945 in Europe). The village of Jasienica was the place where he was recuperating from his wounds. He used this name to hide from the communists.
He was always in trouble with the government because of is outspoken views concerning freedom of speech and expression. In the 1960s he started his history books and got into more trouble over censorship. Wow! What a life!!!

As a young officer in Polish Army

Late 1960s with his secret police wife Zofia Darowska O'Bretenny