The flushing toilet was invented in 1596, not by Thomas Crapper as
most people think, but by Sir John Harington. Harington, a British
nobleman and godson of Queen Elizabeth I, invented a valve that
when pulled would release water from a water closet. Sir John
recommended flushing the toilet once or twice a day, although with
our modern technology, we know that is probably not sufficient.
(Rumor has it that, in Robin Hood's day, King Richard the Lionheart
- angry with how his brother, Prince John, ruled the country while
the King was gone, named fair toilette, 'the john' - AKA as 'the
Jon' to you folks.)
Sir John Harrington invented the first flush toilet in the late
1500's. I have even heard that he installed it for Queen Elizabeth
1st, and she affectionately referred to it as her "John", but have
no idea if that is true. I believe he actually installed the first
toilet in his own mansion.