Mid-February Holiday Notes

15 February - Statehood Day (Дан државности) (Serbia)
Commemorates the outbreak of the First Serbian Uprising (1804) against the Ottoman Empire; also on the same day in 1835 the adoption of the first modern Serbian constitution.
The day is also known as Сретење (Sretenje) ('meeting'), which is actually a church holiday celebrating the Presentation of Jesus in the Temple, 40 days after his birth. (It corresponds to Candlemas in Western churches, which is celebrated earlier because of the calendar difference.)
https://en.wikipedia.org/wiki/Statehood_Day_(Serbia)
https://en.wikipedia.org/wiki/Presentation_of_Jesus
16 February - Day of the Restoration of the State of Lithuania
This is for 16/2/1918, at the Vilnius Conference, when delegates signed the Act of Independence (Lietuvos Nepriklausomybės Aktas).
https://www.lrs.lt/pls/inter/w5_show?p_r=5691&p_k=2
https://en.wikipedia.org/wiki/Act_of_Independence_of_Lithuania
17 February - Washington's Birthday (USA)
I remember this from what I learned about the USA in childhood.
"Washington's Birthday" is the first movement of Charles Ives' "New England Holidays" symphony.
They (the USAnians) had Lincoln's Birthday, too, also in February.
Then things got complicated. This explains it all:
https://en.wikipedia.org/wiki/Presidents%27_Day
Warning: The Uniform Monday Holiday Act is involved.