On the Sunday after Easter in 1506, in Lisbon, more than 500 but perhaps as many as 4,000 people were murdered in a series of religious riots that went on for several days. Most of those killed were New Christians, Cristaos Novos, although a number of un-converted Jews and Old Christians were also caught up in the violence. Many of the perpetrators were then themselves executed as punishment by the Governor, acting in response to the very upset King, who was himself under pressure from the Pope to show a strong response.
Recall that in the decade after the Catholics Kings completed the conquest of Spain and the expulsion of the remaining Jews and Muslims in 1492, their policy became to either convert, leave, or die. Leaving was difficult since the neighboring kingdoms, including Portugal, had also criminalized non-christians, so many chose to convert. Unfortunately for those who settled in Lisbon, the local population hated the converts even more than those who kept their faiths. For these unfortunates, the outcome become both convert and die.
Here on the forum archives are mentions of the signage and plaque that commemorate the massacre, including in Rick's kids' blog entries, but there they blame superstition about drought as the underlying cause, and in the wikipedia entry they rationalize this as part of the general habit of blaming the plague on a scapegoat. Both these are ways of avoiding facing the hatred and greed and xenophobia that boiled over at that season in Portugal --
the murders were committed by a range of people, including German and Dutch maritime traders residing in the city, Dominican officials, and those who just took the opportunity of a tumult-in-progress to loot the goods and property of their neighbors.
I've been reading some of the journal articles about the events, but the quotations in Portuguese and German from the original eyewitness accounts are not easy to follow when I can only read Spanish and English. Also, a lot of the records of this period were lost in the earthquake that occurred on All Saints Day in 1755, when something like 30,000 people perished.
The first Sunday after Easter is called Divine Mercy - in the Bible, God and his spokesmen often warn that retribution for crimes will be visited on succeeding generations. So, the some thousands who were killed (horribly -- beaten, burned, defenestrated on to pikes held below the windows, and so on ) that day were requited with many thousands who died on All Saints about 250 years later.
https://jewishencyclopedia.com/articles/1627-anusim
https://en.wikipedia.org/wiki/Lisbon_massacre
https://www.britannica.com/event/Lisbon-earthquake-of-1755