In the Francken family of Antwerp in the 16th and 17th centuries there were 3 generations of painters with the same Christian names of Frans, Hieronymous, or Ambrosius. At the time, this was an effective sales method for ensuring continuity of the family business, but today's legacy is some confusion in the classification of paintings not differing widely in style or execution. When Frans I's son Frans II reached his majority and began to sign paintings, Frans I described himself as "the elder" in contradistinction to his son, who signed himself "the younger". But this happened again in the next generation when Frans II's son Frans III reached his majority; Frans II took the name of the elder, whilst Frans III adopted that of Frans the younger.
Read more about Francken: Family Tree