BASHYAZI (Heb. בשיצי; traditional Rabbanite transcription for the Turkish name Bashyatchi), family of Karaite scholars in Adrianople and Constantinople. Although the family moved to Constantinople in 1455, they retained the cognomen "Adrianopolitans" even in later generations. The Karaite school of Adrianople tended toward liberalism. The Bashyazi family, its leading exponents, advocated the kindling of Sabbath lights contrary to the prevalent Karaite custom of spending Sabbath in darkness. menahem b. joseph bashyazi first permitted this practice around 1440. His grandson Elijah found support for this ruling in liberal Karaite halakhic sources and through his influence it was accepted in the Karaite communities of Turkey, Crimea, Poland, and Lithuania, although in Egypt, Syria, and Ereẓ Israel the Karaites continued to refrain from kindling lights on the Sabbath at least until the 19th century. Menahem also abolished the Karaite custom of starting the weekly Torah readings from the beginning of the Pentateuch in the month of Nisan and directed that the cycle should start in Tishri, conforming to Rabbanite practice. The more conservative Karaites opposed the change.
His grandson elijah b. moses (c. 1420–1490) was the ideologist of the Karaite rapprochement with Rabbanism and a codifier of Karaite law. Elijah, in addition to upholding the rulings of his grandfather Menahem and father Moses, provided them with a theoretical basis and expanded them (e.g., concerning intercalation). He remains the supreme Karaite authority. Elijah is reported to have begun the compilation of his great code Adderet Eliyahu in about 1480, but the section on the calendar refers to the year 1457. After his death his pupil and son-in-law Caleb *Afendopolo attempted to complete the work. The Adderet was distributed chapter by chapter and its contents were recognized as binding even during the author's lifetime. It was also one of the first Karaite works to appear in print (Constantinople, 1530–31; Eupatoria, 1835; Odessa, 1870 [the latter repr. Ramle 1966]). Its Sabbath laws became the subject of much Karaite polemical literature. Other sections, especially those dealing with the sanctification of the new moon (Elijah was the first to draw up an official calendar for this, which was virtually a permanent one), the ten principles of faith (new and final formulation of the Karaite credo), and the laws of sheḥitah and incest were submitted to a series of adaptations, abridgments, and interpretations by Karaite religious leaders in different countries. Bashyazi's leniency on Karaite halakha stands in juxtaposition to the strict positions of *Aaron ben Elijah. In addition to reflecting the various schools of late medieval Karaite thought, the Adderet attests to Bashyazi's knowledge of both general and Jewish subjects. In the statements and sections concerning beliefs Bashyazi often tends towards Aristotelian positions.
Particularly noteworthy is Elijah's use of Rabbanite techniques and sources, even where they were antagonistic to Karaism. Elijah interpreted their hostility as a device to achieve publicity so as to cover their actual sympathy toward Karaism. However, he also polemicized against several Rabbanite scholars, including Mordecai *Comtino. While one of his three polemical works, Iggeret ha-Yerushah (published in the Eupatoria edition of Adderet), is directed against the Rabbanites, his Iggeret ha-Ẓom and Iggeret Gid ha-Nasheh are written to refute his Karaite opponents. Elijah's correspondence with Karaite leaders in Lithuania shows that his reputation had spread to the northern Karaite communities. He introduced the Lithuanian Karaites to his relaxation of Karaite halakhah and customs, recommending the establishment of a bet din of three in *Troki on the model of that in Constantinople, and the institution of kindling the Sabbath lights. His pupils included the Rabbanite *Moses of Kiev (with whom he also had sharp disputes), well-known among Lithuanian Karaites. The Karaite prayerbook contains several prayers and hymns composed by Elijah, including Meliẓat ha-Mitzvot, recited on Shavuot.
MOSES (first half of 16th century), great-grandson of Elijah, died relatively young. He renewed the connections with the Arabic-speaking Karaite communities. He also traveled to the East, returning with ancient Karaite manuscripts in Arabic and isolated pages of Sefer ha-Mitzvot by *Anan b. David in Aramaic on which he based his Zevaḥ Pesaḥ and Sefer Re'uven (in manuscript). His explanation of the laws of incest, Sefer Yehudah, was published by I. Markon, and an important part of his Matteh Elohim, on the history of the Karaite schism, was incorporated into *Mordecai b. Nisan's Sefer David Mordekhai.
S. Poznański, Karaite Literary Opponents of Saadiah Gaon (1908), 82–85; idem, in: Zekher Ẓaddikim (1920), 33–34; R. Mahler, Ha-Kara'im (1949), 286–7: Danon, in: JQR, 15 (1926/27), 305–7, 311–2; 17 (1924/25) 168–9; Mann, Texts, 2 (1935), index s.v.Elyah ben Moses Bashiatzi; L. Nemoy (ed.), Karaite Anthology (1952), 236–70; Ankori, in: PAAJR, 24 (1955), 11; idem, in: Tarbiz, 25 (1955/56), 44–65, 183–201; idem, Karaites in Byzantium (1959), index; idem, Beit Bashyazi ve-Takkanotav (1966). add. bibliography: D. Lasker, in: Jerusalem Studies in Jewish Thought, 3 (1984), 405–425; S.B. Bowman, The Jews of Byzantium (1204–1453) (1985), index; J-C. Attias, Le commentaire biblique: Mordekhai Komtino ou l'hermeneutique du dialogue (Paris, 1991), index; M. Polliack (ed.), Karaite Judaism: A Guide to Its History and Literary Sources, (2003), index, s.v. "Bashyachi."