 As the political situation worsened , Britain declared war on France , placing all British subjects in France in considerable danger . To protect Wollstonecraft , Imlay registered her as his wife in 1793 , even though they were not married . Some of her friends were not so lucky ; many , like Thomas Paine , were arrested , and some were even guillotined . ( Wollstonecraft 's sisters believed she had been imprisoned . ) After she left France , she continued to refer to herself as " Mrs Imlay " , even to her sisters , in order to bestow legitimacy upon her child . 
