According to this article, flamenco has deep Jewish roots in addition to Indian, Greek, Roman and Persian influences.
The article begins with the art form's Indian roots, brought by Gypsies who traveled from northwest India to Pakistan and Persia into 14th-15th-century Europe and into Andalucia in southern Spain. Some historians say the music's debut might have been as early as 711 CE, brought by Arab armies coming from North Africa.
Andalucian music is an amalgam of Arabic music with Hindu, Greek, Hebrew, Persian influences with local folk music and dances dating back to Phoenician and Roman times.
Following the Spanish recapture of Granada - and the conversion and expulsion of its Muslims and Jews - flamenco "became a voice of protest of dissenting Christians, outlaws, Muslims, Jews and other social outcasts who did not fit into the new political order. Jews were forced to convert to Christianity or leave Spain and Gypsies were forced to settle down and put an end to their nomadic lifestyle."
Further, after the 1492 Expulsion, a Jewish voice "resurfaced" in flamenco.
The plaintive wailing of religious prayer, now forbidden, became the secular "aaiiee" of the conversos (Jews forced to convert to Christianity), with the notable exception of the Saeta. The Saeta sung today during Holy Week dates back centuries and is generally agreed to have Jewish origins. One can imagine the conversos singing in a very traditional manner for them but changing the words to provide their new faith and Christian devotion: singing, no doubt, with extra verve and passion to dispel any doubts of their sincerity. There are also strong similarities between certain synagogal chants and some early forms of cante flamenco.
One section concerns the Peteneras form of flamenco, which is likely linked to Sephardim who settled in Turkey and other Middle Eastern countries.
The Peteneras, writes the author, was passed down through the generations since the 1492 exile. Another hint as to Peteneras' Jewish origins is that even today, many Gypsies refuse to sing or dance Peteneras and consider it unlucky. The music's status as unlucky may be rooted to the long history of persecution of the Sephardim.