An outbreak of syphilis in Naples which later swept across Europe, and which may have originated from the Columbian Exchange, 69 and the prevalence of other sexually transmitted diseases from the earlier 13th century, may have been causes of this change in attitude. Sumptuary laws became the regulatory norm for prostitutes and included making courtesans "wear a shoulder-knot of a particular color as a badge of their calling" to be able to easily distinguish the prostitute from a respectable woman in society. With the advent of the Protestant Reformation, numbers of Southern German towns closed their brothels in an attempt to eradicate prostitution. Leo Tolstoy 's novel Resurrection describes legal prostitution in 19th-century Russia. A similar situation did norsk jenter sex escort ts oslo in fact exist in the Russian Empire ; prostitutes operating out of government-sanctioned brothels were given yellow internal passports signifying their status and were subjected to weekly physical exams.