[10] In modern Egypt, the period is known as Kouji Nabot[5] or Pi Kogi Enavot[11] (Coptic: Ⲡⲓⲕⲟⲩϫⲓ ⲛ̀ⲁⲃⲟⲧ, Pikouji n'Abot, lit.
[11] In Ethiopia, the period is known as Paguemain,[12] Phagumien (Amharic: ጳጐሜን, Ṗagʷəmen),[13] Pagume,[14] or Pagumay[15] (ጳጉሜ, Ṗagume).
Owing to the lack of a leap day, the calendar slowly cycled relative to the solar year and Gregorian date until the Ptolemaic and Roman eras.
The period of the intercalary month was considered spiritually dangerous[20] and the pharaoh performed a ritual known as "Pacifying Sekhmet" (Sḥtp Sḫmt) to protect himself and the world[21] from that god's plague.
[32] Ptolemy III's Canopus Decree was an attempted calendrical reform in 239 BC which would have inserted a sixth day into the intercalary month, but it was abandoned due to the hostility of the priests[33] and people of Egypt.
[14] Its leap years occur at the same time[40][13] and its dates will also shift forward one day relative to the Gregorian calendar in AD 2100[15] (2092 EC).
[41] The unusual calendar is notably used in Ethiopian tourist information to advertise the country's "thirteen months of sunshine".