Famous for asking Jesus why he doesn't manifest himself to the whole world at the Last Supper, according to some traditions he was killed with Simon while preaching in Persia.  
According to Eusebius, his two grandsons were once mistaken for sons of David by Domitian, but then released.  In his most famous work, which was originally placed in the Antilegomena due to its disputed authenticity, he appeals to Christians to be on their guard against "ungodly persons who pervert the grace of our God into licentiousness and deny our only master Jesus Christ."  Famous for asking Jesus why he doesn't manifest himself to the whole world at the Last Supper, according to some traditions he was killed with Simon while preaching in Persia.  FTP identify this full brother of James the Less who is popularly known as the saint of lost causes.
According to Eusebius, his two grandsons were once mistaken for sons of David by Domitian, but then released.  
Saint Jude