Abraham ben Jacob
Abraham ben Jacob, better known under his Arabic name of Ibrâhîm ibn Ya`qûb al-Tartushi (or al-Ṭurṭûshî) was a 10th-century Hispano-Arabic, Sephardi Jewish traveller, probably a merchant, who may have also engaged in diplomacy and espionage. His family hailed from Moorish-ruled Ṭurṭūšah close to the mouth of the Ebro: he himself may also have lived in Cordova. Written and oral history, as well as his writings suggest that he had a Jewish background. However, it has also been argued by other historians that he was a Muslim of Jewish background, and Bernard Lewis states: "There is some uncertainty to whether he was a professing Jew or a Muslim of Jewish origin."
Nothing is known about his return to 'al-Andalus' (the Muslim-ruled part of the Iberian Peninsula), nor of any further travel. The memoirs and commentaries of his journey, possibly first presented to the Cordovan caliph Al-Hakam II (961–76), have been lost; only excerpts by later authors have been preserved, i.e., in Abu Abdullah al-Bakri's Book of Highways and of Kingdoms.
His work is widely known as providing the first reliable description of the Polish state under Mieszko I, the first historical ruler of Poland. He is also noted for his description of the Vikings living in Hedeby, of the Nakonid fortification at "Dorf Mecklenburg" and of what was, in all likelihood, the nucleus of the later ducal castle and palace at Schwerin. Ibrahim ibn Yaqub has a unique place in Czech history as the first person to mention the city of Prague in writing.
- "Ibrāhīm ibn Ya‛qūb al-Isrā’īlī al-Ṭurṭūshī," by Lutz Richter-Bernburg, in: The Oxford Companion to World Exploration, David Buisseret, editor-in-chief, 2 vols., Oxford UP 2007, I:402b-403b