where does the term night cap come from
Nightcap (beverage) Originally, a "nightcap" was understood to be alcoholic, the idea being that it warms you up and helps you sleep, just like the garment of the same name.[7] That changed in 1930, when the non-alcoholic drink Ovaltine was advertised as "the world's best 'night-cap' to ensure sound, natural sleep".[7] An ingredient of Ovaltine is magnesium which helps to induce relaxation.[8]