Quite a few things. Planets, for example.
Earth
All the planets names are from Roman mythology, not Greek.
Earth is the only planet whose English name does not derive from Greek/Roman mythology. The name "Earth" is of Germanic origin and comes from Old English and Germanic words meaning "ground" or "soil."
Out of the old nine, I would say Earth.
In Greek Mythology, Artemis Roman Mythology, Diana
Earth. Its name in English comes from Old English and Germanic origins, meaning "ground" or "soil," rather than from Greek or Roman mythology like the other planets.
Greek Mythology - Hades Roman Mythology - Pluto
Achilles is actually a Greek hero, and he never ruled anything.
In Greek mythology it is Poseidon and in roman mythology it is Neptune
Hera was from Greek mythology. Her Roman counterpart is Juno. But she's both
M. A. Dwight has written: 'Grecian and Roman mythology for schools' -- subject(s): Classical Mythology 'Grecian and Roman mythology' -- subject(s): Greek Mythology, Roman Mythology 'Grecian and Roman mythology' -- subject(s): Classical Mythology, Greek Mythology, Roman Mythology
Many Roman gods were direct copies of Greek gods simply renamed; as in Zeus becoming Jupiter, Hades becoming Pluto, etc.