If only the abbot could see Justo Jorge Calderon now. With curling peyot dangling below his chin and the long black cloak of his small hassidic sect hanging off his broad shoulders, Calderon sure doesn't look like a Benedictine monk anymore. Besides, he goes by Aharon now, and he's the proud father of three little children. Calderon's story is one of those stranger-than-fiction tales that grows more intriguing the longer it goes on. Fortunately, it's also one he doesn't mind sharing. It begins in a small town outside Buenos Aires, Argentina, where Justo Jorge was born into a family of Roman Catholics. "Today I am a very kosher Jew," the 36-year-old says with a smile, "but once I was a very kosher goy." When Calderon was 12, he says, his parents sent him to a private religious school to get a better education than the public schools provided. Before long he was spending extra time studying with the monks. At 14, he joined the pre-mission seminar. "I was young and idealistic," he explains with a shrug. After high school, with his religious zeal increasing, Calderon went looking for the "ancient, original teachings" of Catholicism. The local Benedictine monastery offered the oldest, "purest" form of Christian life around. Based on a 1,400-year-old order and centered around a largely self-sustaining "holy village," it meant spending most of the day in silence, reflecting on the divine. "The word 'monastery' is derived from the Greek 'monos,' meaning one, or alone. We monks were each one seeking the One," explains Calderon, revealing his divinity student's mind-set. Although Calderon's parents weren't happy about his commitment to the monastic life - he's their only son, and they hoped for grandchildren - the young man felt at home in the Benedictine monastery. At home, that is, until he experienced what he calls "my two surprises." The first came in the monastery's library. One of the largest around, it helped make the monastery famous, Calderon says. Of the thousands of volumes it held, though, one particular book would change his life. "One day," he says, "I chanced upon a Haggada, in Spanish and Hebrew. I was drawn to it, and read it from beginning to end, in amazement." At the end of the Seder service, Calderon read the prayer looking forward to celebrating the Pessah holiday "next year in Jerusalem - Jerusalem rebuilt" and stared at a drawing of the Third Temple. Calderon sat in silence - not his usual contemplative silence, but a stunned silence. "Christianity," he explains, "looks at Judaism as something of an archeological concept, not as something that is still alive, relevant and flourishing... Looking at this prayer at the end of the Haggada, I was shocked that modern Jews still nurtured hopes for the future of their religion." The discovery rocked Calderon, but he was still unsure what to make of it. Shortly thereafter, though, he experienced his second "surprise," which sent his spiritual quest in an entirely unforeseen direction. It came on one of his weekly visits to the abbot of the monastery. Upon entering the abbot's study, Calderon found him poring over a Hebrew Bible. (The abbot, Calderon learned, had once studied in Jerusalem, and was comparing ancient texts.) "I was fascinated by the language," he recalls. "I wanted to know, what secrets are in those letters?" By that point Calderon had spent several years in the monastery and, although he was well on his way to a permanent stay there, he returned to his home for a planned one- or two-year break. Once at home he began attending classes at the Catholic-run university in town and working as a nurse for the Red Cross. But, with his "surprises" spurring him on, Calderon also sought out Jews who would be willing to teach him Hebrew. At the time, conversion was not on his mind. "I just wanted to know how Jesus prayed," he says. On Friday nights, Calderon attended services at a local synagogue ("it was kind of like a Protestant church") where the rabbi agreed to let him join the weekly Hebrew class. He also discovered a Messianic Jewish congregation, and prayed there as well. Thus began a period when, Calderon recalls, he would pray to Jesus while in synagogue on Friday night, and wear a kippa to church on Sunday morning. To Calderon, these interreligious prayer sessions didn't seem like a contradiction. "It sounds strange," he admits, "but at the time, it made sense to me. Judaism was not 'outside' Christianity, but part of it... like an ancestor." Soon, however, something in the Shabbat prayers struck Calderon, and shook the foundations of his faith. It was part of the Saturday morning kiddush, specifically, the passage from Exodus that says: "And the Children of Israel observed the Sabbath, to make the Sabbath for their generations an eternal covenant. Between Me and the Children of Israel it is a sign forever..." "This expression stuck in my mind," Calderon says, repeating the words. "'It is a sign forever.'" "That meant," he says, "that there is an eternal bond, established by God. And since God does not change, then that bond" - the sign observed by Jews, marking Saturday as the Sabbath - "must still be in effect!" Why, Calderon asked himself, would the Church move the Sabbath day to Sunday, if it wasn't really a day sanctified by God? The question was more than a little troubling to Calderon. After all, if Sunday was not really the holy Sabbath, and if God's covenant with the Jews had not been abrogated and superseded by Christianity, then maybe other tenets of the Christian religion were also not true. Maybe, he allowed himself to think, Jesus was not actually the son of God? Calderon stopped going to church. "Everything I believed," he says, "just fell apart." He started a conversion class at the local Reform synagogue. When the synagogue closed down due to financial difficulties, Calderon sought out more Jews and discovered the local Chabad rabbi. Rather than eagerly welcome a new convert, the rabbi at first tried to dissuade Calderon. "He would say, 'Why would you want to be Jewish? We have so many commandments, while non-Jews need only to observe the Noahide laws. Besides, you are already a good person in God's eyes!'" This, however, only made Calderon's desire to convert even greater. "Until then, I had thought that Judaism was a religion of strictness and law, whereas Christianity was a religion of love. But suddenly I realized that it was really the opposite." "You see," he explains, "in Christianity, if you don't believe in Jesus, you can't go to heaven. But in Judaism, there is a place in heaven for everyone; you don't have to be Jewish. So really, Christianity is the religion of strictness, and Judaism is the religion of love!" After a period of "trying it out," Calderon knew that he wanted to convert, and that he wanted to move to Israel to do so. There was just one problem: finances. "A ticket to Israel cost $1,200. As a nurse, I was only making $200 a month. How could I ever afford to go to Israel?" he says. The situation was bleak. But then something happened that would be right at home in a hassidic story, the kind that circulates in the little Stropkover shul in Jerusalem where Calderon is now a gabbai: There was a raffle in Calderon's town, with a grand prize of a new ambulance; he entered. Just before Rosh Hashana, Calderon was informed that he had won the grand prize. He sold the ambulance and, suddenly able to afford the airfare, flew to Israel. At first, Calderon, in his new identity as Aharon, studied at a yeshiva for potential converts. But within a few months the yeshiva had closed. In early 1999, Calderon met Rabbi Eliahu Birnbaum and joined the Spanish speakers' ulpan his wife had just started. Around Rosh Hashana that year, Calderon underwent a brit mila. Before Succot, he entered a mikve and completed his conversion. Back home in Argentina, there was little celebrating going on. Although Calderon's mother was happy that he would, having given up the monastic life, provide her with grandchildren, several family members told Calderon, "If you're Jewish, don't come back here." "A few years earlier, I had realized that love, hate and jealousy were separated only by a fine line," Calderon says. "I made a choice to love the Jewish people. Later, I began to see the hatred that some people in my town had for Jews." Back in Israel, Calderon met and married a Jewish woman who had emigrated from Russia with her family. In yet another strange turn, Calderon's mother-in-law met Russian Orthodox missionaries in Jerusalem and converted to Christianity. "Family gatherings," Calderon says with a knowing shrug, "can get pretty weird."