http://www.treblis.com/Notation/Tempo.html

If I see this 1,000 more times, the grossly oversimplified wild 300-
year old Italian "tempo markings" I will drop dead. This is like
opening a Jane Austen book which has instructions as: read moderately.
Read vigoroulsly. Read in a stacatto manner. It's bullshit and worse
so profoundly outdated one wonders what it is doing in its same
irrelevant form tens if thousands if times on the web. A true
definition? No! Any definition of tempo that exists is tautological,
in its being circular and therefore conveniently always 'right' By
Definition.