Gott Fun Avrohom (Yiddish: גאט פון אברהם) is a prayer written primarily in Yiddish and in some Ashkenazi communities it is recited by women before Havdalah. (Sometimes it is also recited by men as well.)
The Complete ArtScroll Siddur and Siddur Kol Yaakov HaChadash both attribute the prayer to Rabbi Levi Yitzchak of Berditchev.
Today, many women maintain the custom of reciting Gott fun Avrohom before Havdalah. Rabbi Levi Yitzchak of Berditchev, traditionally recognized as the author of this prayer, however, wrote that it should be recited three times by men, women, and children, and that this recitation would help assure success in the ensuing week. - Siddur Eitz Chaim, The Complete ArtScroll Siddur, Nusach Sefard, First Edition page 653.
נמצא בכתבי קודש של הרב הקדוש רבי לוי יצחק מברדיטשוב זצ''ל, בעל המחבד ספר קדושת לוי - סידור קול יעקב החדש, הוצאת הספר אדיר, עמוד 350
Despite all this, I read somewhere online that it was not authored by Rabbi Levi, because Gott fun Avrohom appears in siddurim from before his time! So who is the real author, and who should I believe?