On the 12th of Iyar, 1402, the Jews of Rome were granted "privileges" by Pope Boniface IX. They were given legal right to observe their Shabbat, protection from local oppressive officials, their taxes were reduced and orders were given to treat Jews as full-fledged Roman citizens.
In preparation for the festival of Shavuot, we study one of the six chapters of the Talmud's Ethics of the Fathers ("Avot") on the afternoon of each of the six Shabbatot between Passover and Shavuot; this week we study Chapter Three. (In many communities -- and such is the Chabad custom -- the study cycle is repeated through the summer, until the Shabbat before Rosh Hashanah.)
Tomorrow is the twenty-eighth day of the Omer Count. Since, on the Jewish calendar, the day begins at nightfall of the previous evening, we count the omer for tomorrow's date tonight, after nightfall: "Today is twenty-eight days, which are four weeks, to the Omer." (If you miss the count tonight, you can count the omer all day tomorrow, but without the preceding blessing).
The 49-day "Counting of the Omer" retraces our ancestors' seven-week spiritual journey from the Exodus to Sinai. Each evening we recite a special blessing and count the days and weeks that have passed since the Omer; the 50th day is Shavuot, the festival celebrating the Giving of the Torah at Sinai.
Tonight's Sefirah: Malchut sheb'Netzach -- "Receptiveness in Ambition"
The teachings of Kabbalah explain that there are seven "Divine Attributes" -- Sefirot -- that G-d assumes through which to relate to our existence: Chessed, Gevurah, Tifferet, Netzach, Hod, Yesod and Malchut ("Love", "Strength", "Beauty", "Victory", "Splendor", "Foundation" and "Sovereignty"). In the human being, created in the "image of G-d," the seven sefirot are mirrored in the seven "emotional attributes" of the human soul: Kindness, Restraint, Harmony, Ambition, Humility, Connection and Receptiveness. Each of the seven attributes contain elements of all seven--i.e., "Kindness in Kindness", "Restraint in Kindness", "Harmony in Kindness", etc.--making for a total of forty-nine traits. The 49-day Omer Count is thus a 49-step process of self-refinement, with each day devoted to the "rectification" and perfection of one the forty-nine "sefirot."
Links:
How to count the Omer
The deeper significance of the Omer Count