-The first Tetrad since the Middle Ages, in 1493, saw the expulsion of Jews by the Catholic Spanish Inquisition, which rocked western Europe.

-The second coincided with the establishment of the State of Israel – after thousands of years of struggle – in 1949.

-Strangely, the last one occurred in 1967 – far earlier than expected – precisely at the time of the Six-Day Arab-Israeli War.