At one point in history, this was no longer the case, so the rabbis dropped the requirement that the tassels contain a blue thread. Following the two Jewish revolts against Rome (66 A.D.–70 A.D. and 132 A.D.–135 A.D.), each of which ended in devastating defeats for the Jews, the Jewish community was so impoverished that the requirement of a blue thread was abandoned. In addition, a counterfeit blue dye had been developed which was disqualified by the rabbis for use in tassels or tsitsit (Bava Metsia 61b; Menahot 42–43a; Sifre Num. 115). Apparently the desire to prevent the use of this counterfeit blue also led to dropping the requirement of a blue thread. Since the second century, the tassels have been pure white. Tassels are still attached to the four corners of Jewish prayer shawls (tallit) worn in the synagogue and on the corners of the so-called small tallit or tallit katan worn at all times by strictly observant Jews.