A long time ago when you got old it was BAD because when you get old you would start to lose your vision! That was very bad because some people were very good teachers then they got old and couldn’t teach anymore so they had to go into premature retirement (which would be very bad for the students)! Spectacles were invented by Salvino D’ Armate in 1286. He invented them in Italy.
Also, a long time ago there were bad clocks. So, people could not tell time easy because of the clocks. There was the sun clock, the water clock, and the hourglass (which was more accurate than the other clocks). The mechanical clock was invented by I-Hsing in 723 A.D. He invented it in Europe.
Paper was invented by Ts’ai Lun in 105 A.D. But paper mills weren’t invented 1327 years later. Before paper people were writing on bamboo or early paper made by parchment. Paper mills were invented by John Tate in 1432. He invented them in Switzerland. That’s it!