House Tantor was a House Major that used Atomics against House Corrino and they destroyed Salusa Secundus in the 2nd Millenium AG. For that reason the Imperial capital had to be moved to Kaitain. Emperor Hassik Corrino III lashed out against House Tantor, and declared that the family had to be wiped out. The House had been all but obliterated.
Some of the descendants of House Tantor did survive, and almost ten thousand years later, Hundro Moritani of House Moritani, found out during the War of Assassins of 10,187 AG, that he and his family were secret long-distant offspring of House Tantor. Soon after, the bitter recently childless Moritani, lost the War to House Ecaz and House Atreides, he confronted his times' current Corrino Emperor Shaddam IV, and revealed his ancestry. He then revealed he was going to repeat the ways of House Tantor, and use nuclear weapons to kill everyone assembled on recent battle plain on planet Grumman.
Shaddam, uncaring, sentenced him to be incarcerated; and sent Hundro on a prison frigate in a heighliner, back to Kaitain. Moritani then mysteriously died as his frigate de-pressurized killing him, the last known descendant of House Tantor.