Our Gemara tells the story of a man named Eliezer Ze’ira who was wearing black shoes in the marketplace in Nehardea. When members of the house of the Reish Galuta (the head of the Diaspora community) saw this, they asked him why he was wearing shoes that were not usually worn by members of the Jewish community. He responded that was wearing black as an outward sign of his mourning over the destruction of the Temple. Hearing this they arrested him and jailed him for behaving inappropriately, since they did not believe that his status was high enough to be allowed to mourn the Temple publicly. Only when he entered into a discussion of Jewish law with them, proving that he was a scholar, did he secure his release.
In the generation following the destruction of the second Temple, the Sages set certain limits regarding appropriate signs of mourning, mainly in the realms of celebrations and clothing. Nevertheless, in every generation there were people who, based on the passage in Yeshayahu 61:3, were known as Avelei Yerushalyim – mourners of Jerusalem – who accepted upon themselves other mourning customs, as well.
The shoes that were described in the story looked like those of Roman Centurions but there were differences in the number and color of the laces that indicated different levels of society. Apparently the Jewish community traditionally wore white laces, which distinguished them from the non-Jews, and the Sages viewed wearing shoes that appeared similar to the Romans’ as an attempt to take on non-Jewish traditions. The Me’iri writes that the term used in this story for the color black – ukamei – was a dull black color, while the shoes worn by Romans were a bright black color. Thus, Eliezer Ze’ira was accused of inappropriate mourning, but not of the more serious transgression of dressing like a non-Jew.