The historical context is that the Spanish Civil War and the Catholic martyrs here listed should be seen as a whistle stop along the journey from the atrocities against religion of the French Revolution and the murderous repression of religion by the Soviets in their revolution.
It is sobering to contemplate the instinct toward bloody repression of religion contained deep within the left's DNA.
Good. I used to be neutral on the SCW, thinking both sides villains. After doing some in-depth reading, I understand much more why the right rebelled in Spain. The “Republicans”... Communists, really... were hunting down and killing priests and nuns.
The communists in Spain did what the communists did in the Russian Empire - kill clerics.