Medieval Persian:
Medieval Persian refers to the Persian language and culture during the period from the 6th to the 15th century. It was the era when Persian literature, art, and architecture flourished under various dynasties such as the Sassanian Empire, Samanids, Ghaznavids, Seljuks, and Timurids. During this time, Persian was the language of the court, administration, and literary works.

1. Language:
- Medieval Persian, also known as Classical Persian or Old Persian, was written in the Arabic script and had a significant influence from Arabic.
- It had a complex grammatical structure with a rich vocabulary, including many Arabic loanwords.
- The language was formal and poetic, with a focus on eloquence and aesthetics.

2. Literature:
- Medieval Persian literature reached its zenith during this period, producing renowned works like the Shahnameh (Book of Kings) by Ferdowsi, Divan-e-Hafez by Hafez, and Rubaiyat by Omar Khayyam.
- Poetry played a central role in Persian literature, and various forms such as ghazal, qasida, and masnavi were prevalent.
- Themes often revolved around love, spirituality, nature, and heroic epics.

3. Art and Architecture:
- Persian art and architecture in the medieval period were characterized by intricate geometric patterns, calligraphy, and floral motifs.
- Notable examples include the stunning mosques of Isfahan, such as the Jameh Mosque and Sheikh Lotfollah Mosque, which showcased intricate tilework and domed structures.
- Miniature painting also flourished during this time, with illustrated manuscripts becoming popular.

Modern Persian:
Modern Persian, also known as Farsi, refers to the contemporary Persian language spoken in Iran, Afghanistan, and Tajikistan. It emerged during the Safavid dynasty in the 16th century and has evolved over time.

1. Language:
- Modern Persian is written in the Persian script, an adapted version of the Arabic script, but with additional letters.
- It has simplified grammar compared to Classical Persian and has incorporated more loanwords from other languages such as French, English, and Russian.
- The language is spoken in a more colloquial and informal manner in everyday conversations.

2. Literature:
- Modern Persian literature encompasses a wide range of genres, including novels, short stories, and poetry.
- Prominent modern Persian writers include Sadegh Hedayat, Forough Farrokhzad, and Ahmad Shamlou.
- Contemporary Persian literature explores diverse themes and reflects social, political, and cultural changes.

3. Art and Architecture:
- Modern Persian art and architecture have been influenced by both traditional and Western styles.
- Contemporary Iranian architecture showcases a blend of modern designs with elements of traditional Persian architecture.
- Iranian artists have also embraced various mediums such as painting, sculpture, and installation art.

Conclusion:
The difference between Medieval Persian and modern Persian is primarily seen in the language, literature, and art of the respective periods. Medieval Persian had a more formal and poetic language, with a focus on complex grammatical structures, while modern Persian is simpler and incorporates more loanwords. Similarly, the literature and art of the two periods reflect the cultural and historical contexts in which they emerged