Mike at the Feature Philately YouTube channel reached out to me and suggested doing a research swap. He is a specialist in Bulgarian items, so he sent me a large packet of Bulgarian material, and I sent him some interesting Austrian stuff. He will be releasing a video on his channel at the same time this article is published. Check the link above to see it!

I received a ton of interesting stamps from Mike at Feature Philately!
I’m very ignorant about Bulgarian history and culture, so this is an area that offered many new things to learn. I’ll go through all of the stamps in this packet by catalog number. As I don’t have any specialized catalog for Bulgarian material, these are all listed by Scott catalog number. I scanned all of the stamps at 600 DPI, you should be able to click on any of the below images to see a larger view.
Cataloguing these inspired me to go through the rest of my Bulgarian stuff (none of it I sought out, it was set aside when sorting a bunch of worldwide material). I ended up having a decent bit of stuff, so I might put together a Bulgarian album at some point. If and when I do, I’ll tell Mike — I know that he makes his own album pages and has offered to send them to me. On to the stamps!
I’ve written a little bit about what I’ve learned in regards to each stamp. Some of the subjects depicted don’t really have information to go with it (for instance a stamp depicting a mail plane) so I’ve just listed what the catalog says the subject is. Other topics appear multiple times, therefore I’ve only written about the subject on the first occurrance (e.g. Shipka Pass Monument). I’ve also included catalog numbers as well as printing method and perforation.
General Issues

Scott 74–75 (1907)
Ferdinand in 1887 and 1907. Lithography, perf 11.5
#74–75 are two of three in this series, there is another 25 stotinki value (#76) which is blue.
Ferdinand (Фердинанд) was Tsar of Bulgaria from 1908–1918. He was part of the Saxe-Coburg family, therefore related to the current royal family of England, who changed their family name from Saxe-Coburg to Windsor years later. Ferdinand oversaw the entry of Bulgaria into WWI on the side of the Central Powers, and he abdicated at the end of the war, crowning his son Boris III Tsar.

Scott 420–422 (1942)
The next several groups of stamps are all part of a larger series, 420–433. Photograveure, perf 13
10 stotinki — This stamp features Kubrat, who is credited with starting Old Great Bulgaria in the 600’s CE. Kubrat was ethnically a Hun, however spent his early life in the palace in Constantinople. He helped the then-emperor (Heraclius) form an alliance with the people of the Black Sea/Caspian steppes (modern Ukraine, SW Russia, Georgia, Armenia). This region became “Great Old Bulgaria,” the eventual fall of which — and resulting migration from — led to what is currently Bulgaria.
15 stotinki — Cavalry Charge (The catalog doesn’t specify which cavalry charge when so I’m assuming this has to do with the above and below stamps…)
30 stotinki — The Rider of Madara is a sculpture featuring a man on a horse, driving a spear into a lion. Carved into a large rock in NE Bulgaria, near the village of Madara, it is believed to have been carved sometime during the late 7th/early 8th centuries CE. It is not known what the meaning of the large relief sculpture is, however several plausible explanations are hypothesized based on the culture of the times.

Scott 423–425 (1942)
50 stotinki — The Christening of Boris I is featured on this stamp. Boris I was the ruler of the First Bulgarian Empire from 852–889 CE. He is credited with aiding in the conversion of the region to Christianity, and also promoted the development and use of Cyrillic script, now widely used across Slavic languages.
1 lev — St. Naum (830–910 CE) was a Bulgarian writer and missionary amongst the Slavs who also worked to create and distribute the Cyrillic script. The script was created in the Pliska Literary School, of which Naum was one of the founders.
2 leva — The Crowning of Tsar Simeon by Boris occurred in 893 CE. Simeon ruled until 927. He was the first ruler of the Bulgarian Empire to begin ruling it as a Christian kingdom, and he also oversaw the expansion of Bulgarian territory to its greatest extent, making it the dominant empire in Eastern/Southeastern Europe of the time.

Scott 426–428 (1942)
3 leva — Golden era of Bulgarian Literature (Without more specific information I’m not going to write anything — there are a lot of sources regarding Bulgarian literature, but from what I can tell there is not a single, standard usage of the term “Golden Age” in regards to literature. There is, however, a “Golden Age” of the Bulgarian Empire, usually associated with the reign of Simeon, but I’m not going to assume they are one and the same.)
4 leva — Basil the Bogomil was sentenced to death for Heresy by Constantinople. Basil was a member of a growing sect of Christianity, the Bogomils (founded by a priest of the same name), which rejected the extreme heirarchy of the churches at the time such as the Eastern Orthodox church. The leadership in Constantinopble believed that ordering Basil to appear before the emperor would convince him to recant his beliefs. After several attempts, he refused to recant, and was later burnt at the stake in Constantinople.
5 leva — “Proclamation of Second Bulgarian Empire” — The First Bulgarian Empire was conquered by the Byzantines, and the Bulgarians eventually rebelled in 1185, leading to the creation of the Second Bulgarian Empire. The Second Bulgarian Empire was later conquered by the Ottomans, culminating in the end of the empire in 1422.

Scott 429–431 (1942)
7 leva — Ivan Assen II was Tsar of Bulgaria (1218–1241) during the Second Bulgarian Empire. His father, Ivan Assen I was one of the founders of the empire. This stamp depics him at Trebizond, then part of the Byzantine Empire, at the time under Crusader rule. Ivan Assen II was offered regency of the empire in exchange for ceding parts of occupied territories in what is now Macedonia and Albania.
10 leva — This stamp depicts the deportation of Eftimi (also Euthymius, Evtimiy, Евтимий) in 1393. Tarnovo was the Bulgarian capital at the time, the defense of which was entrusted to Eftimi at the time. The Ottomans attacked the city, which fell after a 3‑month siege. Eftimi was exiled and spent the rest of his life in Thrace. As the capital fell, this was the beginning of the end of the Second Bulgarian Empire.
14 leva — Wandering Minstrel

Scott 432–433 (1942)
20 leva — Monk Paisii (Paisius of Hilendar) was a monk in the 1700s. He is famous for writing one of the first major histories of Bulgaria. Because of this, he is credited with being a major figure in kicking off the Bulgarian National Revivial, which is a period of increased cohesion and national identity of Bulgarians under Ottoman rule.
30 leva — The Shipka Pass Monument is atop Shipka Peak, and it was completed and dedicated in 1934. It commemorates the Liberation of Bulgaria as a whole, but especially the Battle of Shipka Pass, which was a major victory for the Bulgarians (fighting with and for the Russian Empire) against Ottomans for control of the nearby mountain pass — vital for trade and transportation — in 1877–1878.
Airmails

Scott C19-C20 (1940)
The next several groups of stamps are all part of a larger series, C19-C30. Photograveure, perf 13
1 lev — Mail Plane
2 leva — Plane over Tsar Assen’s Tower, a mountain fortress used by Tsar Assen II (see above) as a defense against raiders in the 1200s

Scott C21-C22 (1940)
4 leva — This stamp features a plane over Bachkovo Monastery. Established in the 11th century, it also served as a school, teaching subjects like math, history, and music — in addition to the religious instruction one would expect. It was looted and destroyed by the Ottomans in the 15th century, but rebuilt.
6 leva — The Bojurishte Airport, near the capital Sofia, used to be the main airport of Sofia. It then become a military airfield. It is now defunct.

Scott C23-C24 (1940)
10 leva — Plane, train, and motorcycle
12 leva- I’m not completely sure based on the description of this stamp and comparing the design to pictures — but I believe this to be the National Art Gallery in Bulgaria. The Gallery occupies the former royal palace, and was initially turned into the National Art Gallery at the onset of communist rule, when the monarchy was abolished.

Scott C25-C26 (1940)
16 leva — This plane is over the Pirin Mountains, a small range of mountains south of Sofia. The highest peak is Vihren, at 9,564 feet (2,915 m) above sea level. The fertile and easily-defended areas in the foothills beneath these mountains have been inhabited since prehistoric times.
19 leva — The Rila Monastery, established in the tenth century, is featured on this stamp. Much like the Bachkovo Monaestery featured above, it was an early culktural and educational center in Bulgaria, and is considered an important piece of the creation of the Bulgarian national and cultural identity.

Scott C27-C28 (1940)
30 leva — This stamp features a plane and a swallow. In Bulgaria, many people believe that swallows bring happiness and good luck. A white swallow, being especially rare, are believed to indicate especially good fortune.
45 leva — The Alexander Nevsky Cathedral in Sofia was built from 1882–1912, and is the largest cathedral in the Balkan region. Materials used in construction come from all over Europe. It was designed to be reminiscent of Byzantine architecture.

Scott C29-C30 (1940)
70 leva — Plane over Shipka Monument (see above)
100 leva — Plane and royal cipher

Scott C31-C32 (1945)
Overprinted on Scott 368 and 370 (typography, perf 13)
These stamps, and the next sets, all feature overprints from the Bulgarian Fatherland Front (Отечествен фронт, abbreviated ОФ - Otechestven Front). During WWII, several pro-communist groups merged to become the Fatherland Front, with the goal of opposing the (then) pro-German dictatorship in Bulgaria. After the USSR declared war on Bulgaria in 1944, the ОФ carried out a coup and declared war on the Axis powers. Communism took hold in Bulgaria at this time — and the ОФ existed until it’s eventual dissolution in 1990 when communism in Eastern Europe fell. These overprints represent some of the last issues before the communist propaganda types that were issued for many years thereafter.

Scott C37-C38 (1945)
These and the next pair of stamps are all part of a larger series, C37-C40. Overprinted in various colors on Parcel Post stamps from 1944 (Q29 — 100l), lithography, imperforate.

Scott C39-C40 (1945)
Many thanks to Mike at Feature Philately for this wonderful exercise!
Thanks Mike! I’ve had a blast learning about these stamps as well as Bulgarian history and culture…a subject I had not yet had a reason to learn about.
If you’ve found an inaccuracy in any of this — please drop me a line and I’ll be sure to update it. Bulgaria isn’t an area (geographically or philatelically) that I’m super familiar with, so I’ve pieced this together via a variety of sources.