The McNaughts were one of the most powerful of the old Great Houses that possessed the Malathon system. They had a tradition of cautious and shrewd leadership. Their forces were sizeable and well trained, supported by three lesser houses from the neighboring Kalakh? system.
Their forces were obliterated during the Fremen Jihad by a force of ten Fremen? legions (300000 men, less than 1/10 of the McNaught size).
Source: Dune Encyclopedia?,