Due to his advanced age and his inability to relocate to America, Martin's brother Denny Fairfax was unable to properly protect and maintain his American possessions and conveyed by deed on August 30, 1797, to James Markham Marshall "all and every of those divers tracts, pieces and parcels of land, being part and parcel of the proprietary of the Northern Neck of Va., with all beneficial right and interest of whatsoever nature the same may be". This conveyance thus terminated the Fairfax and Martin families' interest in the proprietary. In 1799, the Virginia General Assembly authorized Marshall as the legal titleholder of Fairfax's remaining landholdings. The Northern Neck Proprietary was officially dissolved in 1806 when Virginia again became its legal owner.