It’s sad to note that so much of ancient Greek and Roman knowledge, particularly in engineering, was lost during the Medieval period. The loss of the Great Library at Alexandria (Egypt) probably didn’t help.
Much was “lost”, yes, but much was preserved.
Good reference:
“How the Irish Saved Civilization” by Thomas Cahill
In light of that book, and others, the so-called ‘dark ages” is a misnomer.
That term “Medieval” gets used too loosely for my taste. Greek and Roman knowledge was lost during the ‘Dark Ages’ or Early Middle Ages, which ended in 700AD. The Great Library at Alexandria was destroyed no later than this date.
The distinction is important because in the true Medieval Period (1000 to 1300) Europeans built the great Cathedrals, using techniques the Romans never knew.