Classic postal envelope from Romania, circulated in the second half of the 19th century to a historical destination in the Balkans. 
Postage stamp: The letter is franked with a Romanian stamp from the issues with King Carol I (left profile), 
with a face value of 25 bani. The design type indicates a classic issue "Carol I with a beard". 
Destination: The envelope is addressed in French to Monsieur P.M. Mattheoff / pour Madame M. Mattheoff 
in the town of Philippopoli, mentioning the region of Roumelie Orientale (Oriental Rumelia). 
This is an autonomous province created within the Ottoman Empire by the Treaty of Berlin (1878), 
which was later united with the Principality of Bulgaria in 1885. 
The city of Philippopoli is known today as Plovdiv (Bulgaria). 
The envelope represents a special piece of Balkan postal history, documenting postal relations between 
the Kingdom/Principality of Romania and the ephemeral autonomous province of Eastern Rumelia.

The back of the envelope contains three transit and arrival stamps that perfectly describe the letter's journey in 1881: 
Departure scancel (Bucharest): Type: Round stamp with double circle, text BUCHAREST CENTRAL. 
Date: 15 NOV. 81 11 10 (November 15, 1881, 11:10). T
his confirms the exact year the letter was circulated (correlating with the date of November 14 on the front of the envelope). 
Transit cancel (Constantinople - Ottoman Post Office):Type: Small circular stamp with bilingual characters 
(French and Arabic/Ottoman).
Text: The text CONSTANTINOPLE is partially distinguishable.Date: 17 NOV. 81 (November 17, 1881). 
The letter passed through the capital of the Ottoman Empire to be redirected to the province of Eastern Rumelia. 
Arrival cancel (Philippopoli):
Type: Simple circular stamp with the name of the destination city: PHILIPPOPOLI.Date: 19 11 81 (November 19, 1881). 
The envelope reached its destination in just 4 days after departure. 
The presence of all clear stamps on the reverse provides a complete story and attests to the originality of the postal circuit 
(the piece is not an artificial philatelic creation). 
Black edges indicate a "mourning cover", a dedicated and sought-after category in postal history.