Eliezer Kallir, is considered one of the greatest paytanim. He authored some of the most well known piyyutim including those said for geshem and tal, as well as many others (although most of his piyyutim that were included in the Rosh haShana and Yom Kippur prayers are no longer said by most). While his literary output is well-known, "[b]iographical facts about Kallir are shrouded in mystery." E.J. (new ed.) vol. 11, p. 743. There are many theories about who R. Kallir was and I would like to touch on some of these in this post. (Also see below for a bibliography on R. Eliezer Kallir - provided by a kind reader of the blog.)
R. Shmuel David Luzzato (Shadal) in his Mevo l'Machzor Beni Roma, discusses Kallir and the history of piyyutim at length. "If you will ask who authored the first piyyut and who followed them, I will answer that the first is Yanni or Yinai, and the second is R. Eliezer Berebi Kalir. The product of both is apparent to all in the Haggadah as the piyyut "Az Rov Nissim" is from Yanni . . . and the piyyut "Ometz Gevoroteha" is from R. Eliezer berbi Kallir . . ." Interestingly, "regarding Yanni a nasty rumor has been spread (Zunz found it in a manuscript commentary to the Mahzor), however, anyone who hears it will laugh, . . . [and the rumor is] that Yanni became jealous of his student R. Eliezer and [Yanni] put a scorpion in [Eliezer Kallir's] shoe and the scorpion killed Kallir." Shadal, however, dismisses this rumor in light of the fact that Yanni's piyyutim are still said, especially the one mentioned above during Pesach. Shadal argues that if Yanni was a murderer then there is no way Yanni's piyyutim would be so popular. Additionally, Rabbenu Gershom mentions Yanni and uses honorific terms, something Rabbenu Gershom would not have done if the rumor is true.
Shadal then turns to the details of R. Eliezer Kallir's biography. "In many places R. Eliezer signs his name as 'R. Eliezer beribi Kallir from Kiryat Sefer.' Many of the early ones believed that this indicated Kallir was from the biblical town of Kiryat Sefer, and many thought that Kallir was a tanna, either R. Eliezer the son of Simon ... or R. Eliezer ben Arakh, both of these opinions are recorded in the Sefer HaYuchsin." Shadal, however shows that it is highly unlikely that R. Eliezer Kallir was a tanna or that he was from the biblical town of Kiryat Sefer. Instead, Shadal quotes the opinion of R. Moshe Landau (grandson of the Noda Be-Yehuda) in his commentary to the Arukh, Maarkhe Lashon. According to Landau Kallir is a reference to the Sardinian city Cagliari. Shadal disagrees with Landau. In the end, after citing other opinions, including identifying Kallir with an Italian city, Pumadisa in Babylon, and Sippara also in Babylon, and to those it should be added, Bari, Ostia, "Civitas Portas, the former port of Rome (Derenbourg); Constantinople; Civita di Penna in the Abruzzi; . . . Normandy, Speyer in Germany . . . Lettere in Souther Italy, . . . Antioch and Hama in Syria . . . Kallirrhoe in Palestine . .. [and finally] Tiberias." E.J. p. 744. As should be apparent, there is no consensus on where Kallir was from.
Turning to his name - Kallir - the starting place is R. Nathan and his Arukh. He explains that Kallir, means cake (indeed in Greek kalura means cake). And, Kallir was called "cake" because "he ate a cake that had written on a kemiah (amulet) and, as a result, he became smart." Arukh erekh klr. The idea to feed children cake with inscriptions is a well documented one. R. Eliezer from Worms, the author of the Rokekh records the custom to feed children cakes with the verses from Isaiah 50:4, id.50:5, and Ezekiel 3:3. The children would eat these when they were indoctrinated into Torah study on Shavout. Of course, as noted above, some view the name Kallir as an indication of where Kallir was from. Indeed, many, including Shadal did not swallow (if I may) the Arukh's interpretation of Kallir.
Again, as we have seen there is a bit of debate when it comes to Kallir, one of the more interesting debates regards which piyyutim can be attributed to him. While in many Kallir provides his name in an acrostic, according to R. Shelomo Yehuda Rapoport (Shir) one can also attribute those piyyutim that there is a gematria that equals some permutation of Kallir's name. That is, Kallir sometimes signed his name Eliezer haKallir, Eliezer beribi Kallir, Eliezer Kallir me-Kiryat Sefer, and a combination of any of these. Thus, according to Shir, if in the first line equaled any of these Kallir was the author.
R. Efraim Mehlsack, however, took issue with Shir's use of gematria. Specifically, Mehlsack wrote Sefer ha-Ravyah, Ofen, 1837, against Shir. Mehlsack was a prolific author, he supposedly authored some 72 seforim, but the only published sefer was this one. But before we get into the details regarding Mehlsack we need to discuss his critique of Shir. Mehlsack went to town on Shir and showed that using the gematria for the first line of a book, Mehlsack could make Kallir the author of just about every important Jewish book. Mehlsack goes through Tanakh and uses the first verse of each book to equal some form of Kallir's name. For example, the first verse in Berashit equals 913 which equals "meni ha-katan Eliezer Kallir." The first verse in Joshua equals 1041 which equals "ha-katon Eliezer beribi Kallir." Mehlsack doesn't stop with Tanakh, he then moves to Mishna noting that the first mishna in Berkhot is 2362 which equals "ani Eliezer berbi Ya'akov ha-Kallir mi-Kiryat Sefer yezkeh be-tov amen." As a final shot at Shir, Mehlsack has the gematria of I am Shelmo Yehuda Rapoport = 1164 to Eliezer beRebi Yaakov Kallir =1164. Indeed, Mehlsack was not content to provide some 40 odd examples, he had even more and as a result of already printing the pages, the Sefer Ravyah is an interesting bibliographical oddity in that these gematrias appear on page 18 and then continue. Well Mehlsack includes an alternative page 18 in the back which has more examples of these gematrias. Thus, the book goes until page 32 and then there is another page 18. Both versions appear below.
Turning now to Mehlsack. As I mentioned Mehlsack supposedly authored 72 books. We know of 34 titles from that list. Although most of those works have been lost, there are a
few, around five, that are available in manuscript. In Boaz Hass's recent book on the history of the Zohar, he mentions Mehlsack's translation of the Zohar (Scholem also discusses this work). One of the works lost, is a work permitting one to travel via train on Shabbat. The introduction of this work has been published (in part) and appears below. Additionally, Sefer Ravyah was not Mehlsack's only attack on Rapoport, Mehlsack attacked Rapoport in a few of his works, and some of his critiques were published in Bikkurei Ha-Ittim.
Returning to Kallir, it goes without saying that Kallir's piyyutim were controversial. Most famously, the Ibn Ezra complained about them and offered that one should refrain from saying Kallir's piyyutim. Ibn Ezra's critique is discussed by R. Eliezer Fleckels, who defends Kallir, and Heidenheim thought it important enough to include this lengthy responsum in Heidenheim's edition of the Machzor.[For more on the Ibn Ezra see צבי מלאכי "אברהם אבן-עזרא נגד אלעזר הקליר - ביקורת בראי הדורות" פלס (תשם) 273-296)
Bibliography on R. Eliezer Kallir (provided by a kind reader of the blog.)
אלבוגן, התפלה בישראל בהתפתחותה ההסטורית, 233 - 239
יוסף זליגר, "לתולדות הפיוט והפיטנים (ר' אלעזר קליר)", כתבי הרב ד"ר יוסף זליגר, לאה זליגר מו"ל, ירושלים תרצ, צז - קב
שלמה דוד לוצאטו, אגרות שד"ל א, 464 ואילך
---, הליכות קדם, גבריאל פאלק, אמסטרדם תרז, מחלקה שניה, 56 - 64.
צבי מלאכי, "הפייטן אלעזר הקליר - לחקר שמו ומקומו", באורח מדע: פרקים בתרבות ישראל מוגים לאהרן מירסקי במלאות לו שבעים שנה, צבי מלאכי, מכון הברמן למחקרי ספרות, לוד תשמו, 539 - 543
אהרן מרקוס, ברזילי: מסה בתולדות הלשון העברית, ירושלים: מוסד הרב קוק תשמג, 346
עזרא פליישר, תרביץ נ, 282 - 302
---, "לפתרון שאלת זמנו ומקום פעילותו של ר' אלעזר בירבי קיליר", תרביץ נד ג, ניסן - סיון תשמה, 383 - 427
שלמה יהודה ראפאפארט, תולדות גדולי ישראל, 24 - 55
יעקב שור, ספר העתים, 364 – 365
בנועם שיח: פרקים מתולדות ספרותנו, מכון הברמן למחקרי ספרות, לוד תשמג, 114 - 156
המעין טז א, תשרי תשלו, 3 - 14. המשך: ב, טבת תשלו, 32 - 52.
 Mevo leMachzor Beni Roma, Habermann ed. Jerusalem
 For more on this commentary see S. Brisman, History & Guide to Judaic Dictionaries & Concordances, KTAV Publishing House, Inc. 2000, pp. 19-20.
 For more on this custom see Assaf, Mekorot le-Tolodot ha-Hinukh be-Yisrael, Jerusalem 2002, pp. 80-1 n.9 and the sources cited therein. See also, E. Kanarfogel, Peering through the Lattices, Wayne State University Press, Detroit, 2000 pp. 140-41 and the notes therein (discussing the ceremony generally); id.p. 237 n.47 (discussing some of the halakhik issues with this custom including the "issue" of "excret[ing] these verses")
 See G. Kressel, "Kitvei Mehlsack," Kiryat Sefer 17, pp. 87-96.