Pajamas’ history
Original pajamas were lightweight trousers tied around the waist and worn in Asia.
When the British Empire conquered Asia, wearing pajamas is one of the influences they got from Asia.
From the original garment, the two-piece clothing was conceptualized in the form of a jacket which closes down the front with button, and trouser combination. By the early 20th century, pajamas replaced nightshirts as the dominant style of sleepwear for men and women.