Israel must ease the conversion and immigration process, particularly for the descendants of conversos, those forced to convert to Catholicism in medieval Spain, the chairman of the Jewish Agency said on Tuesday.

“Spain is making an effort to return the descendants of Jews expelled from Spain in 1492,” Natan Sharansky said at an Ashdod Conference on Aliyah and Absorption, referring to a new bill in Spain to give Sephardic Jews, whose ancestors were exiled in 1492, dual citizenship privileges.

“It is important to note that, according to estimates, there are millions of descendants of conversos, including hundreds of thousands who are exploring ways of returning to their Jewish roots. The State of Israel must ease the way for their return,” he said.

According to a contested study from 2008, published in the American Journal of Human Genetics, some 19.8 percent of Spanish and Portuguese men were found to carry genetic traces linked to Sephardic Jewry.

Sharansky encouraged the rabbinate to be more lenient in regards to conversions to Judaism.

“The State of Israel must approach the conversion issue in a friendly manner, in accordance with the tradition of Beit Hillel (the Academy of Hillel, which existed in the first century BCE and was known for its lenient religious rulings), and must hold its doors open to those who wish to join the Jewish people,” he said.

Conversions in Israel are overseen by the Chief Rabbinate, which has repeatedly come under fire for being too stringent, and for solely recognizing the ritual if performed according to strict Orthodox interpretations of Jewish law. The issue manifests itself most apparently in the approval of the Jewish status of new immigrants who come to Israel having undergone conversion in countries outside of the country.