Thymus regress with age?

the thymus initially increases in size and then decreases in size from adolescence through old age.

The thymus is so small in older people it appears as though it is not there. It shrivels up after puberty or so.

The middle ages showed regress in that a vast amount of human knowledge was lost, coupled with poorer living conditions for much of the world's population due to this loss of scientific knowledge,...

The Renaissance Age was th age after the Middle ages.

Ages and ages and ages means a really long time.