On this day in 1941, Commonwealth forces and Free French forces invaded French Syria.
The campaign is remarkable for a variety of reasons, including the use of cavalry by both sides. The action was made necessary by legitimate British fears that Vichy would allow the Germans to occupy Syria, a threat made credible, if only from the Allied prospective, by the airborne invasion of Crete which had just occurred and by Vichy allowing the Luftwaffe airport rights in Syria. Indeed, the action had been proceeded by Royal Air Force strikes on French airfields and retaliatory French raids on British ones in Transjordan.
The campaign was short, but it was marked by notable French resistance to the Commonwealth invasion and a decline of an offer of German Luftwaffe assistance. The action overall is one of several that cast some legitimate doubt on the common concept of all Frenchmen being pro Ally at the time.
Surprisingly, the action did not result in a Vichy declaration of war against the United Kingdom and in fact Vichy's forces in Syria fairly rapidly fell in spite of their stout resistance. The British had battlefield superiority, but this required diversion of Commonwealth forces from Libya, where their loss was keenly felt. The action also, however, saw the deployment of Free French forces in what might be regarded as a near civil war being fought, and really for the first time, in a French colony.
The Free French were given military administration of Syria and Lebanon following the Allied victory, something that more or less made it clear that the British at least were recognizing a rival claim to the governance of France. That administration, in keeping with the spirt of the age, recognized the independence of Lebanon and Syria, with Lebanon achieving a real measure of independence that Syria did not. Lebanon declared war on the Axis powers in 1943.
DeGaulle, who was effectively the head of the Free French state by the war's end, was not sympathetic to Syrian independence and as with Algeria, the end of the war brought on demands for immediate statehood. Demonstrations in Damascus turned violent in May, 1945 which resulted in French troops being deployed inside of Syria to quite the demonstrations. This didn't work and the British intervened with their troops having authorization to fire on the French if necessary, which it did not turn out to be, one of two instances of the British intervening in favor of a post war independence movement against a European colonial power (the other being in the Dutch East Indies). This ended with the French leaving and the British briefly staying, until they were able to withdraw.