An early Christian alphabet, introduced in Moravia (present day Czech republic, Slovakia), then spread to Croatia, Bulgaria etc.  Rites had been conducted previously in Greek but it was an attempt to reach out to Slavic people, and maintain independence from Constantinople.  Use continued for 1000 years in Croatia!
The letters are fantastically ornate.  Some eg Sha are lifted from Hebrew (same meaning too), others have a vague resemblance to Greek.
Printed on the Ivan Mestrovic Mausoleum door in Cavtat.
Love the meanings of the letter names too – Know, Speak, Good, Exist, Earth, Tree, How, People, Thought, Peace, Solid, Knowledge…