The proper adjective is Roman (of or from Rome, or the Roman Empire).
The sound-alike word is roaming (moving about).
Roman (in katakana) = ロマン
In Roman numerals 13 is XIII.
11 is XI in Roman numerals.
MM
If you spell him Amor, he is.
Ρωμαϊκός [RomaeekOs]
II
un roman
They called him Neptune.
LXXXIX.
Penny
Just the way you spell them today. They haven't changed. The only change was from the Greek to the Roman.