The Cretan State was a short-lived protectorate on the island of Crete, after yet another tussle between the Cretans and their Ottoman rulers (in 1897) and before the transfer of sovereignty over to the Kingdom of Greece (ultimately recognized in 1913). Britain, France, Italy, Austria-Hungary, and Russia decided the Ottomans could no longer control the land and interceded, declaring the foundation of the Cretan State and each taking turns administering the so-called autonomous state. The Cretans ultimately took matters into their own hands and declared enosis (Ένωσις), or union, with Greece. Crete has been a part of Greece ever since [well, union was declared in 1908 and finally recognized by the Great Powers in 1913].
Stamp details: Stamp on top: Issued on: December 3, 1898 From: English Offices, Cretan State MC #2
Second row: Issued in: 1899 From: Russian Offices, Cretan State MC #5, 7
Third row: Issued on: March 1, 1900 From: Chania, Cretan State MC #1-3
Stamp on bottom: Issued on: August 28, 1907 From: Chania, Cretan State MC #28
Recognized as a sovereign state by the UN: No Claimed by: Hellenic Republic Member of the Universal Postal Union: No