Sometimes proving you are Jewish requires extreme measures; in Yehosha Bloomberg’s case, he had to venture 100 years back in time.

Bloomberg, 24, moved to Israel from Chicago in 2007. He served in the Israel Defense Forces in a special unit for new immigrants. In two months’ time he plans to marry his beloved, Naomi, 21, whom he met during his academic studies.

In Israel, if a bride or groom was born abroad or if their parents got married abroad, they are generally asked by the regional rabbinical court to undergo a process called “birur yahadut” (proof of Judiasm), which requires submitting documents attesting to their Jewish heritage.

In preparation for the happy day, Yehosha discovered that to register for marriage he would have to prove he is a Jew. Taking a cue from his immigrant friends’ bitter experiences with the rabbinical bureaucracy in Israel, he began searching for proof of his Judaism. What he found exceeded his expectations: a 100-year-old document classifying his great-grandmother as a member of the “Jewish race.”

“First I Googled my name,” Yehosha described the search. “I found a family tree someone had created using documents tracing back to my great-grandmother, who emigrated from Europe to the U.S. Her name was clearly stated, and it said that she arrived in the U.S. at age 16 and registered as a slave, or, more accurately, a housekeeper. Her country of origin was listed as Russia and in the race section it said HEBREW.”

Yehosha sent the ancient document to the Rabbinical Court in Chicago, where it was decided that the document serves as sufficient proof of his Jewish heritage. “I don’t want to think about what would have happened if I hadn’t found this rare document,” he said. “It is very exciting.”

Rabbi Shaul Farber, the chairman of the non-profit organization ITIM Resources and Advocacy for Jewish Life, said that Bloomberg’s story points to a serious problem in the marriage system in Israel: “We at ITIM see cases like Yehosha’s every day. Sometimes we find creative solutions, like looking in various archives. But sometimes there is no solution.”

Farber went on to say that in the last year, the rabbinate opened more than 5,000 cases of birur yahadut. “The rabbinical court system needs to operate on the assumption that people who seek their services are, in fact, Jews, and recognize that when people who are clearly Jewish approach them, as was the case here, they should do everything in their power to assist them.”