Wrong use of the with proper nouns in the possessive,
Don't say:
The Euripides' tragedies are famous.
Say:
Euripides' tragedies are famous.
Note:
If the name ends m on s or x or is difficult to pronounce with the extra syllable's we omit the final's Mana Callas' voice is divine. Don't use the definite article with proper nouns in the possessive case.