He was father of another Richard Owen Theodor, the fifth, born 27 May 1611, who became Sheriff in 1657 and died in 1665. His son, the last Richard Owen Theodor (1645-1669), died without issue. His immediate heiress was his daughter Margaret Owen Theodor, wife of Coningsby Williams of Glan-y-gor, and after her childless death Penmynydd passed through her aunt, Mary Owen Theodor, wife of Rowland Bulkeley of Porthamel, to their son Francis, whose dissolute ways forced him to sell the inheritance to a Bulkeley cousin.