The Anav (or Anau, as they were known in Rome) family was one of the most ancient Jewish families in Italy. According to their family tradition, they were descendants of four aristocratic Jerusalem families who were deported to Rome by Titus after the Destruction of the Second Temple in 70 CE.
Along with the Kalonymus family, they founded the yeshiva in Rome in the 8th (or 9th) century. When the Kalonymus family moved to Germany, they became the recognized scholarly leaders of Italy from the 10th-14th centuries. Yechiel b Abraham Anav was the head of the Yeshiva of Rome in the mid-11th centuries. His son, Nathan ben Yechiel Anav, wrote the Aruch.
Sources: Gates to Jewish Heritage