The custom of sending Shanah Tovah greeting cards to celebrate the New Year can be traced back to the ancient Chinese and Egyptians. The Germans are known to have printed New Year's greetings from woodcuts as early as 1400. Jews began sending messages some decades earlier as well.
Rabbi Shalom (d. 1413) of Wiener Neustadt (Austria) was a prominent spiritual leader of German Jews at the time. In a book written by his student, Rabbi Yaakov Levy Moelin (מהרי״ל 1387-1427), R. Shalom is quoted regarding what one should write in such New Year’s greeting cards, already in the 14th century:
“Rabbi Shalom of Wiener Neustadt says: Once Elul (the Jewish 11th month) begins, when one writes a personal letter to his friend, one must mention at the beginning that he hopes and prays that his friend will have a good year, along the lines of, ‘May you be written and sealed for a good year,’ [בשנה טובה תכתב ותחתם] or ‘May the One who suspends the Earth over the void give you a [good] inscription and sealing,’ [תולה ארץ על בלימה ישיב לך כתיבה וחתימה] or something similar. This was also the practice of Rabbi Yaakov Levy.”
The recommendation of beginning with the wish that the recipient be “written and sealed” is referring to the most important theme of the Jewish New Year holy day season: That one is judged and hopes to be written and sealed in the Book of Life. “Inscribe us and seal us in the Book of Life” is repeated in the liturgy and blessings every day for ten days from Rosh Hashanah through the end of Yom Kippur. The Jewish year begins with Rosh-Hashanah (New Year ראש השנה) and on that occasion, according to the Talmud, God writes it God’s judgment about every individual for the year ahead.
“ Three books are opened on Rosh Hashanah before the Holy One: One of wholly wicked people, one of wholly righteous people, and one of mediocre people whose good and bad deeds are equally balanced. Wholly righteous people are immediately written and sealed for life; wholly wicked people are immediately written and sealed for death; and mediocre people [most of us] are left with their judgment suspended from Rosh Hashanah until Yom Kippur”.
According to this tradition the average person has ten days from New Year’s eve through the the Day of Atonement to achieve more good deeds and to repent for what they have failed to do in the year that has passed. One who is blessed, who has repented (teshuvah) and prayed (tefillah) and given charity/tzedakah will not only be inscribed in the Book of Life, but that person will also be sealed in the Book of Life for another year. In Hebrew the name of this ten day period is: “The days of terror– ימים נוראים” and also as “The ten days of repentance – עשרת ימי תשובה”.
Given that one’s fate hangs in the balance, it is particularly meaningful to be early and send greeting cards offering blessings for the year ahead and a reminder to do good and ask for forgiveness.
The 14th century tradition of the German Jews to mention this need of repentance in writing spread world wide with the development of the print and postal services. Greetings vertions veried like “Good and sweet year” and “May this year and its curses soon be over, may the new year begin with its blessings”. Spacial artistic greeting cards (named in Hebrew “GoodYears - Shanot-Tovot – שנות טובות”) used to be very popular. During the seconed half of the 20th century telephone calls replaced the cards that in turn made a comeback with the 21st century move to social media.