Short answers, pulled from the story.
German forces executed 335 Italian prisoners in disused quarries near Via Ardeatina as a reprisal for the Via Rasella attack. The victims included men ranging from 15 to 70 years old and comprised doctors lawyers workers shopkeepers artists teachers students and teenage boys.
Luftwaffe Generalmajor Kurt Mälzer decided that killings called for reprisals after SS Obersturmbannführer Herbert Kappler arrived at the scene. Adolf Hitler authorized the reprisal stipulating it be carried out within 24 hours while General Eberhard von Mackensen endorsed the recommendation.
Only 75 of the 335 selected for death in caves were Jewish despite common misconceptions about their predominance among victims. Wilhelm Harster suggested making up numbers from 57 Jews also in Nazi custody but most victims came from every walk of life including rich and poor.
Herbert Kappler was sentenced to life imprisonment but escaped in August 1977 before dying on the 9th of February 1978 at home in Soltau West Germany. He had supervised the investigation and agreed with General Mälzer that ten Italians should die for each German policeman killed.
Vatican archives dated the 24th of March 1944 contained intelligence gathered hours after the attack showing the Vatican heard Germans planning to punish Italian citizens tenfold SS deaths received only five hours before the massacre took place. The Secretariat Vatican believed the attack undertaken Via Rasella would provoke occupiers excessively repressive act increase people hatred Germans.