The marriage record for Cornelis Johannes and Susannah Elizabeth Ferreira shows that on that date, 25 April 1841, both of them were 'Minderjarig' - ie <21 years old. Cornelis Johannes must therefore have been born AFTER 25 April 1820 rather than before. See here: https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSV8-89L2-4?i=130&...
