Dunash ben Labrat
Dunash ben Labrat, also known as, Rabbi Adonim Halevy (ha-Levi), lived in Spain in the middle of the tenth century. He studied with Saadia Gaon and served as a rabbi, possibly in Cordoba at the same time that Menachem ben Jacob ibn Saruk, Hisdai ibn Shaprut's secretary, was working on his biblical dictionary. A grammarian and piyyutam (liturgical poet), Dunash'a works include the Shabbat song Dror Yikra and Dvai Hasair, the (now) traditional preface to birkat hamazon at weddings.
Dunash wrote a series of responsa against Menachem and presented them, with praise and thanks, to Hisdai. He claimed to have disputed 200 items, but in the text which has been preserved there are only 160 entries. Many of Dunash's comments dealt with Menachem's explanations which, in his opinion, were likely to lead to error in matters of halachah and belief. This religious factor may explain the severity of his attack.
Though Menachem was fired as a result of accusations of heresy, there is no proof that Dunash deliberately caused his downfall or that he benefitted from it in any way.
Three of Menachem's students, Isaac ibn Kapron, Isaac ibn Gikatilla, and Judah Hayyuj, came out against Dunash by writing responsa dealing with 50 items. Dunash's student, Yehudi ben Sheshet answered back sharply.
Rashi, who knew of the argument between the school of Menachem and the school of Dunash, quotes Dunash about 20 times. R. Tam wrote "decisions" on the disagreements between Dunash and Menachem.
The greatest controversy between these scholars was the nature of the Hebrew root. We know today that Hebrew words are made up of three-letter roots. This was not known in the medieval Jewish world. Both Menachem and Dunash were incorrect in their grammatical analyses because they assumed that some roots could be one or two letters.
Despite this controversy, Dunash was best-known for his poetry. He was the first Jewish poet to apply Arabic forms of poetry to Hebrew, thus laying the foundation for medieval poetry. It raised quite a stir at first, but soon secular Hebrew poetry using classical forms became the rage of Spain. Solomon ibn Gabirol, writing a poem praising Judah HaLevi, referred to Dunash as the greatest poet of all time.
Only a few of Dunash's poems have so far been discovered and most are known only by lines quoted elsewhere. A Cairo Geniza fragment indicates that ten rhymed riddles, previously thought to be the work of Ibn Gabirol, were written by Dunash. He also wrote piyyutim.
A Poem by Dunash ben Labrat
Source: Gates to Jewish Heritage