Русско-англо-русский юридический словарь

sound mind and memory – n. having an understanding of one's actions and reasonable knowledge of one's family, possessions and surroundings. This is a phrase often included in the introductory paragraph of a will in which the testator (writer of the will) declares that he/she is "of sound mind and memory." (The People's Law Dictionary by Gerald and Kathleen Hill)

He concluded that Serabjit-Singh was of “sound mind and memory” and was not under “any undue influence” when she signed her last will. (The Buffalo News)

I, James Daniel Flanngan of proffitt, Albmarle County, Va., being of sound and disposing mind do hereby make, publish and declare this my last will and testament, revoking all others. (Court Records: Last Will and Testaments, University of Virginia)