[Calpernia]

>>> it was not a republic until december 1964, a full year later.

Then what is their National Holiday, Jamuhuri Day - December 12, 1963?

[Mount Athos]

Then what is their National Holiday, Jamuhuri Day - December 12, 1963?

Jamhuri is the Swahili word for "republic", a holiday to mark Kenya's establishment as a republic on 12 December, 1964.

Kenya also gained independence exactly one year before this, on Dec 12th 1963. So they can celebrate both independence and becoming a republic on the same day, despite these events being one year apart.

Independence Dec 12th 1963
Republic Dec 12th 1964