John Sinclair, Master of Caithness Peerage person ID=20723 (d. 1575) Parents George Sinclair, 4th Earl of Caithness Lady Elizabeth Graham Children George Sinclair unknown Sinclair Sir James Sinclair Marie Sinclair Sir John Sinclair Siblings William Sinclair of Mey unknown daughter Sinclair unknown Sinclair Lady Margaret Sinclair Lady Barbara Sinclair George Sinclair of Mey David Sinclair Lady Agnes Sinclair Partners Jean Hepburn