Complex sentence: Released in November 1945 after an amnesty he refused to emigrate and instead elected to stay in Poland and continue his activity in the anti-communist opposition; at that time he wrote his memoires ("Wspomnienia 1939-1945" published in Paris in 1977).
Split into simpler sentences: Released in November 1945 after an amnesty, he refused to emigrate and instead elected to stay in Poland and continue his activity in the anti-communist opposition. During that time, he wrote his memoirs ("Wspomnienia 1939-1945", published in Paris in 1977).