It was in May of 1935 when a prototype aircraft made by the Bayersche Flugzeug Werke first took to the sky. That plane was made according to specifications issued by the German Luftwaffe for a single seat fighter aircraft and with it getting airborne, a legend was created.

The Very first Messerschmitt BF 109 prototype.
In the years that followed the BF/Me 109 proved itself a force to be reconed with but it wasn't just the aircraft itself that made it a winner, it also was circumstances in which it was used that made the difference. Because many of the airforces in the world at the time were still using Biplanes which had great manoeuvrability and according to militairy protocol that was the key to have a superior fighting aircraft. Speed and armament were considered to be insignificant, if one could out turn the opposing pilot they would be safe. As such, more thought went out to the development of heavy bombers with the technology that should have been used in fighters: they had to be quick, heavy armored and sleek. Ironically, later in the second world war, that strategy proved to be valid as the Boeing B17 and the Avro Lancaster pummeled Germany into submission.
The 109's contenders in the contest were all designed according to the "manoeuvrability is key" and many of them were either based on Biplane technology or had non retractible landing gear, which reduced speed. Only the competing Heinkel 112 posed a serious competition.
The competitors to the Me 109

The Arado AR-80

The Focke-Wulf Fw 159

The Heinkel He 112
The Messerschmitt was chosen because the Heinkel and the Arado were too heavy and the Focke-Wulf proved to be unreliable.
The 109 first saw action on Franco's side in the Spanish Civil war where it faced Sovyet made Fighters such as the Polikarpow 115 Biplane and the Polikarpow I-16 "Rata" and British made fighters such as the Gloster Gladiator Biplane which were all planes designed by the "manoeuvrability is key" protocol. The Condor Legion had a field day with the republicans' airforce, showing that Victory was in speed rather than manoeuvrability.

An Me 109 C in service with the Condor Legion during the Spanish civil war
That should have been a warning sign but military protocol was slow in those days and preparations for war in neighboring countries to Germany were equally slow and disastrous.
Take for example the Royal Netherlands Army air force. In the years prior to outbreak of war the mobilisation wasn't given a high priority and the fighters they had in frontline service were hopelessly inadequate for the Job. They had the Fokker D21 which again was designed with the "manoeuvrability is key" rule in mind.

And they had the Douglas 8A-3N which actually was a light bomber, never designed for arial combat, but it was the only aircraft that was readily available and thus was ordered and pushed into service.

To further complicate matters, the Dutch parlament fell twice before the war started making a modernisation of the air force even more difficult. More modern Fighters like the Fokker D23, the Koolhoven FK58 (Itself a more develloped version of the Fokker D21), The Curtiss P36 Hawk and the Hawker Hurricane couldn't be ordered and delivered in time. But what really did the Dutch Airforce in was the result of yet another military protocol: to place the planes in a neat row on the airfields.

Fokker T5 bombers on a Dutch airfield, neatly in a row.

Belgian Hawker Hurricanes on an airfield neatly in a row. It was much the same in France, Poland and other theatres of war.
So the Germans fitted their fighters with powerful cannons rather than the customary machine guns, making it possible to take out entire squadrons with a single strafing run. And once the opposing airforce is done, the paratroopers are brought in, making it possible for the Germans to overtake the Maginot line and other fortified borders. The opposing forces were waiting on the ground for the tanks to show up, expecting another trench war like the military high command had trained them for, instead they saw transport planes with paratroopers flying over and dropping the troops behind their lines unopposed, since their airforces were destroyed on the ground.
But it was during the war in Fance that the Me 109 first would face its match.

The Vickers Supermarine Spitfire.
Built to similar configuration as the Me 109, the Spitfire actually went into service earlier but development of the aircraft took a little longer and by the time the Spitfire and the 109 battled each other the German pilots had more experience and those early clashes ended up in the 109's favor. But at the battle of Britain the tables began to turn on the 109 because many pilot from Polish, Dutch, French and Belgian airforces had fled to Great Britain and were now getting back at the Germans in what then was the most cutting edge fighter aircraft of the day. They brought along experience to the Royal Airforce and had the enormous advantage of flying over friendly territory all the time. If they were shot down, they would be at their own squadrons only a few hours later.
During the Battle of Britain shortcomings of the 109 began to emerge, the major one was a shortage of fuel for sustained flight over the channel and into Britain. That was because with the strategy of Blitzkrieg, the German forces would capture the airfields of occupied countries and used those to fortify their advance. In the Battle of Brittain that advantage was lost, not to mention that captured Luftwaffe pilots had no means of escaping a POW camp and be back in axis controlled countries.
The second shortcoming but no less serious, was due to the Me 109's high and narrow landing gear. Because the Me 109 was designed for easy production, the gear was connected to the fuselage before the wings were attached.

Me 109's in production, the landing gear can be seen just behind the engine, already in place waiting for their wings to be attached.
But that also meant that it was an unstable aircraft on the ground and many were lost in landing or taxi accidents. The undercarriage also made the Me 109 a difficult plane to land anywhere else but on a paved runway. More aircraft were lost to landing and take off accidents than to aerial combat
As a result, later German fighters such as the Focke-Wulf 190 were designed with wide undercarriages and durability, it made them harder to build but it kept losses in landing accidents low.

The Focke-Wulf 190
Even stronger, when Messersmchitt propesed a successor to the 109 the 209, they incorporated the wider undercarriage but priortity was given to further improve the 109 rather than replacing it with a new untested design that took time to perfect and Time wasn't on germany's side in those days.

The Me 209, it never went into full scale production.
After the war the Me 109 remained in service with several airforces and was adapted to stay in service for much longer than anticipated although that usually meant that the builders of those aircraft had to look elsewhere for powerplants since the Daimler-Benz engines that powered the Me 109 became scarce.
In Spain that resulted into the Hispano Ha1110 "Tripala" which was powered by a Spanish build Hispano-Suiza engine and the Ha1112 "Buchon" (Dove) which was powered by the engine of the Supermarine Spitfire: The Rolls Royce Merlin.

The Tripala
The Buchon
In Tzecho-Slovakia they installed Junkers-made engines which were actually meant for Bomber aircraft, the resulting Avia S199 had such a notoriously stubborn flying cgaricaristic that pilots nicknamed them "Mezek" (Mule)

A Mezek trainer aircraft, which shows that the weak undercarriage still was claiming aircraft after the war. The Mezek also has been used as a frontline fighter by Isreal which is a big irony no matter how you slice it.

The 109 in Israelian service.
In the sixties the 109's Merlin powered Cousin the Ha 1112 Buchon became a movie star. When the production for the movie "Battle of Britain" was underway, the production decided that they'd use genuine Luftwaffe aircraft rather than painted over Mustangs or the likes. They found their Luftwaffe in Spain where the airforce was still flying their Buchons as trainers. Many Buchon was painted over in German markings and that's how many of them remain today.

A Buchon in Luftwaffe colors, the four bladed propellor and the high nose however show that it's not a real German 109.
And even stranger, here's a couple of Buchons painted to look like P 51 Mustangs, they even have a faux airscoop fitted. The "Messerstang" was used by the same movie production who gave us "The Battle of Britain" in the "Patton" movie. Apparently, it was easier to use the Buchons they already had than to aquire genuine P 51 Mustangs.
Not many airworthy Me 109's exist, most of them are either Buchons or Buchons that have been retrofitted with Daimler-Benz engines. Genuine airworthy 109's are around but very rarely seen at airshows and people who do fly them are extremely cautious with this rare plane.

A beautiful restored BF 109 E-4, one can tell it apart from the Buchon by it having the squared off wingtips and the old style bonnet. One can tell by looking, that this is not a Buchon with a retrofitted Daimler engine.
So it's the 75'th birthday of one of the most notorious aircraft in the history of aviation. And I'm pretty sure that the
Hundert-neun will continue to be a source of both inspiration and fear for many years to come.