Gen. Wojciech Jaruzelski, the last Communist leader of Poland, who sent tanks to crush Solidarity’s stirrings for democracy in 1981 and went on to preside over the death of the system that had nurtured him, died on Sunday in Warsaw. He was 90.

The cause was complications of a stroke he suffered in early May, officials at the Military Medical Institute in Warsaw said in a statement. He had spent many of his last months at the institute, where he had also been treated for cancer.

General Jaruzelski led a government that was deeply unpopular in Poland through most of the 1980s. For decades before that, as a career officer and party official, he dutifully worked to entrench Soviet-directed Communism in Poland, an effort that even Stalin, its instigator, recognized as futile, likening it to “putting a saddle on a cow.”

On Dec. 13, 1981, the dour general with tinted glasses, a weak jaw and a ramrod posture set in motion events that would earn him a villainous place in history. On that night, as most Poles slept, he declared martial law and ordered troops to suppress the powerful Solidarity trade union movement, whose demands for greater freedoms were alarming politburos from East Berlin to Moscow.