Verses with the word persian in the Old Testament (2 verses):

Nehemiah 12:22
The Levites in the days of Eliashib, Joiada, and Johanan, and Jaddua, were recorded chief of the fathers: also the priests, to the reign of Darius the Persian.

Daniel 6:28
So this Daniel prospered in the reign of Darius, and in the reign of Cyrus the Persian.