Responsa  Responsa (Latin: plural of , 'answer') comprise a body of written decisions and rulings given by legal scholars in response to questions addressed to them. In the modern era, the term is used to describe decisions and rulings made by scholars in historic religious law. Roman law recognised , i.e. the responses and thoughts of jurists, as one of the sources of (written law), along with laws originating from magistrates, from the Senate, or from the emperor. A particularly well-known and highly influential example of such responsa was the Digesta (or Digests), in 90 books, principal work of the prominent Second Century jurist Salvius Julianus. This was a systematic treatise on civil and praetorian law, consisting of responsa on real and hypothetical cases, cited by many later Roman legal writers. In the Roman Catholic Church, a responsum is an answer given by the Congregation for the Doctrine of the Faith on certain matters pertaining to faith and morals. The Holy Office is the sole and exclusive doctrinal organization which has the right to give responsa. Recent doctrinal documents which contain relevant responsa are Commentary on Responsa ad quaestiones, Responsum ad Dubium Concerning the Teaching Contained in Ordinatio Sacerdotalis and Responses to Certain Questions of the United States Conference of Catholic Bishops Concerning Artificial Nutrition and Hydration. In rabbinic literature, the Responsa are known as "She'elot u-Teshuvot" ( "questions and answers"), and comprise the body of written decisions and rulings given by poskim ("deciders of Jewish law"). A modern term, used mainly for questions on the internet, is "Ask the rabbi". Judaism's responsa constitute a special class of rabbinic literature, to be distinguished from the commentaries ("meforshim")—devoted to the exegesis of the Hebrew Bible, the Mishnah, the Talmud—and from the codes of law which delineate the rules for ordinary incidents of life. The responsa literature covers a period of 1,700 years—the mode, style, and subject matter have changed as a function of the travels of the Jewish people and of the development of other halakhic literature, particularly the codes. Responsa play a particularly important role in Jewish law. The questions forwarded are usually practical, and often concerned with new contingencies for which no provision has been made in the codes of law, and the responsa thus supplement the codes.