Rabbi Yitzchak ben Yehuda ibn Gayyat, one of the great Rishonim (Early Talmud commentators and codifiers), lived in the generation after the Gaonim period came to an end. The great Talmud luminaries of that generation continued the work of the Gaonim in the interpretation of the Talmud and the formulation of the Halachah-the practical application of Jewish law in the daily life and conduct. The decisions of the Gaonim, derived from the Talmud, were further expanded by new Halachic decisions based upon them and upon the Talmud itself. This is how the vast and important Rabbinic literature of the Rishonim was created in the centuries following the Gaonic period.

Rabbi Yitzchak ibn Gayyat was one of five outstanding Talmudic and Halachic authorities, all named Yitzchak, who lived around the same time. The others were: Rabbi Yitzchak ben Baruch Albalia, grandfather of Rabbi Abraham ibn Daud the first Rabbi Yitzchak bar Moshe, successor to Rav Hai Gaon, Rabbi Yitzchak ben Reuven Albarceloni, a grandfather of the Ramban, and Rabbi Yitzchak Alfasi (RIF) who outshone the others.

Rabbi Yitzchak ibn Gayyat was born about the year 4790 (1030) in a distinguished family of Torah scholars that flourished in the Spanish city of Lucena, not far from Cordova.

He distinguished himself from early boyhood with extraordinary mental capacities. As a young scholar he attracted the attention of Rabbi Shmuel Hanagid, the Grand Vizier of King Badis. Rabbi Shmuel took the young scholar under his wing and provided him with all his needs, so that he could concentrate on his learning. On his part Rabbi Yitzchak became greatly attached to Rabbi Shmuel who was an outstanding Talmud scholar in his own right.

When his benefactor died, Rabbi Yitzchak ibn Gayyat was about 25 years old -about the same age as Rabbi Joseph Hanagid, who succeeded his father Rabbi Shmuel as Grand Vizier as well as head of the Jewish community. The two young men became very fond of each other, and their friendship lasted for ten years-until the untimely death of the young Jewish statesman at the hands of a murderous mob in Granada on Shabbos, 9th of Teveth, 4826 (1066). Almost the entire Jewish community of Granada was destroyed in that bloody massacre. Very few Jews escaped that blood-bath, among them Joseph's wife, who was the daughter of Rabbi Nissim of Keirwan, and their young son Azariah.

The widow and son, together with the other refugees, came to Lucena, where Rabbi Yitzchak ibn Gayyat headed the Yeshiva. The community took care of the refugees. Rabbi Yitzchak took it upon himself to care for the widow and her son, and prevailed upon the leaders of the community to hold the position of Rabbi open for Azariah. He himself undertook to teach and prepare the young lad for his Rabbinic post. Unfortunately, Azariah died young. Thereupon the community elected Rabbi Yitzchak as both Rabbi and Rosh Yeshivah of Lucena.

As already mentioned, Rabbi Yitzchak ibn Gayyat was one of the greatest Talmudic authorities in his time. He wrote commentaries on the Mishnah and Talmud which, unfortunately, were lost in the course of time. He is quoted, however, in works of other great Talmudists of his time and later. Thus his works suffered the same fate as works of other great Talmudic scholars of that time. One of the reasons for this is that these works were overshadowed by the greatest commentator and teacher of all times Rabbi Shlomo Yitzchaki (Rashi). Also the works of the RIF and Rambam took the spotlight away from other works written in those generations. Not being as popular and in demand as the works of Rashi, the RIF and Rambam, other works, though of great merit, were not copied much, so that in the course of time the manuscripts became lost.

One of Rabbi Yitzchak ibn Gayyat's works has been preserved, however. It is Halachoth Ketuloth (Comprehensive Laws). It is primarily devoted to laws of holiday observance and prayer, such as the laws of Megillah (Purim), Pesach, Havdala, Kiddush, Rosh Chodesh, Counting the Omer, laws of Teshuvah, Rosh Hashanah, Yom Kippur, Chol Hamoed, Hallel, Lulav, Succah, Tisha B'Av, and laws of mourning. One of the great merits of this code of laws is that it contains decisions by the Gaonim whose original works have been lost.

Rabbi Yitzchak ibn Gayyat wrote also a philosophical work in the form of a commentary on the Book of Koheleth (read during Succoth in some congregations). But this work also was lost. In addition to his vast Talmudic knowledge, ibn Gayyat was an outstanding Hebrew grammarian. He is mentioned by Rabbi Abraham ibn Ezra and Rabbi David Kimchi (RaDaK). However, his works in this field were lost, too.

Better known is Rabbi Yitzchak ibn Gayyat for his sacred poetry. His piyyutim are deep and not easily understood. But already in the time of his disciple Rabbi Moshe ibn Ezra were the piyyutim of Ibn Gayyat widely known and recognized. Many of them were included in the machzorim (festival prayer books) of various communities in France, Italy, and North Africa. They have an honorable place among the piyyutim of other great Rishonim, such as those of Rabbeinu Gershon Meor Hagolalo and Rashi. Rabbi Yitzchak ibn Gayyat composed Piyyutim for all the prayers of Yom Kippur (Maariv, Shacharith, Musaf, including the Avodah and Neilah). He also composed many Selichoth (penitential poems), as well as piyyutim for Shabbos and Yom Tov. Many of the Piyyutim have the acrostic (verse initials) reading "Yitzchak ben Rabbi Yehuda Gayyat, Chazzak"; sometime also "Alisani" (of Lucena).

About the age of 59, Rabbi Yitzchak ibn Gayyat became seriously ill. He went to Cordova for medical treatment. Here he died on the day of Shabbos. His body was brought to Lucena where he was laid to rest with great honor.

After his death, the RIF took over the leadership of the Yeshivah of Lucena, when he had to flee from Fez at the age of 75. The RIF headed the Yeshiva until he died at the ripe old age of 90 (in the year 4863/1103).