The last of the Elders (z'keinim) who were contemporaries of Joshua and outlived him, passed away in the year 2533 after creation. They were part of the chain of Torah transmission as listed at the beginning of Ethics of the Fathers: "Moses received the Torah from Sinai and gave it over to Joshua. Joshua gave it over to the Elders, the Elders to the Prophets..."
In ancient times, this day was marked as a fast day.
[Some are of the opinion that this occurred on the 5th of Shevat].
Chabad-Lubavitch Chassidim observe the special customs of the Shabbat prior to the yahrtzeit (anniversary of the passing) of the sixth Lubavitcher Rebbe, Rabbi Yosef Yitzchak Schneersohn (1880-1950), which occurs next week, on the 10th of Shevat.
Link: A Letter from the Lubavitcher Rebbe outlining his suggested observances for the Shabbat preceding Rabbi Yosef Yitzchak's yahrtzeit.
The mandate of the whole of Creation is stated almost immediately.
They translate it as “Let there be light.”
But it is better translated as, “It should be light.”
Meaning that all the world—even the darkness—should become a source of light and wisdom.
And that mandate He put in our hands.