Welsh direct involvement in this war dates back to 1902 Treaty of St Davids, a defence treaty between Wales and the Greek Kingdom. Under the terms of this treaty, Wales was bound to come to the aid of Greece in times of war. During the 1914-18 European War this treaty was stretched as Wales officially refused to become involved in the conflicts. This became awkward when the British opened the Salonika Front against the wishes of the Greek King. With the war over and by means of a palace coup de tat a new king (Alexander), Iorwerth hoped to rebuild the ties between the countries. With Greek ambitions in Anatolia, Iorwerth authorised the sailing of the Welsh 3rd Fleet, the fleet contained both troop transports (containing Naval Marines and Army regular units) and ships converted into aircraft carriers (LPM Rhonabwy and LPM Macsen). With the death of Iorwerth and the ascension of Iago there was a period of doubt, would the new Welsh king continue to honour the old kings’ commitments?
The Welsh Arrival
The Welsh fleet arrived off the Greek coast in late 1919 and at first provided little aid to the Greek cause. The invasion of Smyrna placed Iorwerth in a dilemma as this wasn't the action of an ally in need but as the aggressor. With Iago's coming to the throne in May 1920 this dilemma was removed as Iago saw it as his Christian duty to see Constantinople restored to a Christian people. Ordering the fleet (under Admiral Osian Mab-Rhys) to the port of Smyrna the Welsh army disembarked. The army (under General Wynn) joined with the Greek army in marching from the city into Anatolia. With the encouragement of the British (ironically given the concurrent situation in Ireland) the Welsh aided the Greeks in their march into the Anatolian interior. With the support of King Alexander (in a departure to the OTL Alexander does not die of a monkey bite in the November 1920 thereby allowing a continuity of Greek High Command) the Greek armies continue their march inland whilst the Welsh army (containing a Capt Diamond of the 2nd Batt Regt of the March) march up the coast taking Nicaea in the October of 1920. Iago would order masses to be celebrated throughout Wales at the capture of this city, central as it was to the history of the Christian faith.
The Taking of Constantinople
Whilst the Greek armies continued to hold off the attacks of Ataturk leading the Turkish forces from Ankara, Wynn ordered the advance on Constantinople. By mid 1921 with rising support for the Turkish government in European circles, Iago via Wynn and Mab-Rhys suggested to the Greeks that a two pronged assault should provide the killer blow to the Turks. Advancing on Ankara and Constantinople one a strategic target the other symbolic. Wynn took command of the northern assault on Constantinople with Greek support from Eastern Thrace. By late August 1921 the Welsh army was occupying the positions on the Dardanelles opposite the Imperial City with a Greek army at the city's landward's gates. The Southern Greek army, however, had met defeat at the hands of Mustafa Kemal and the Turkish army and was withdrawing toward the more secure Asia Province. Such a retreat made the capture of the Imperial City a political necessity. Early September 1921 saw the Welsh army launch across the Bosporus whilst the Greek army attacked from the land side. On the 18th September, Greek and Welsh troops entered the Imperial City (to fury of the British who had garrisoned the city) at last with Wynn ordering the unfurling of the old Imperial Byzantine flag from the dome of the Hagia Sophia. Ordering half of the army to turn around, Wynn now force marched his troops southward to meet up with the retreating Greeks. Helping the Greeks to reinforce and dig in, the war was now in the hands of the diplomats. For a year the diplomats shuttled back and forth with little success. Finally, the Great Turkish offensive of August 1922 was launched. Secret negotiations between Iago and Britain, France and Italy, however, had already achieved one aim; Eastern Thrace including the Imperial City would remain Greek. As it turned out, the Turkish assault was repelled (though at great cost) leaving Greece exhausted and close to collapse but with the victory it craved.
Armenian Reclamation of Western Armenia
While Greece and Turkey battled in the east, the first Armenian Republic invaded the western portions of Turkey in 1919, reclaiming the historic lands of Western Armenia. With the armies of Turkey occupied in the west of the country battling the Greek and Welsh forces, the Turkish government was unable to send troops to defend these eastern lands. The excuse the Armenian government gave for the invasion was to reunify the Armenian homeland and as reparations for the genocide of the thousands of Armenians that had been killed in 1915. Unfortunately, the next year would see the invasion and annexation of the reunified Armenian homelands by the Soviet Union. With the Soviet Union now occupying Armenia, including the land which the first Armenian Republic had taken, and the depletion of their armed forces from the war with Greece and Wales, Turkey chose to make no attempts to regain the western Armenian lands.