Men primarily, but a substantial number of women, have always had the ability to learn the ways of the Fire. In the beginning, this led many to worship fire. Logical thinkers raised that higher, and began the Temples of the Solarii, who are fire elementals much given to spite and venom with each other and their human worshippers. But then a revelation came, and the teaching of the True Fire came to Alkeman.
This explanation was logically, emotionally, and morally superior to the Temples. That is, it made more sense rationally and philosophically. It was a better, more accurate story. It demanded better behavior of its adherents. And the fact that its early adopters were able to walk through fire without harm, even fire cast by Temple priests, was pretty impressive.
It replaced a celestial chaos with an orderly, yet benevolent universe run by the True Fire rather than the feuding Solarii. With that assumption in place, it made sense for the alchemists to begin to study nature to find out its rules. They began to use their native pyrokinesis powers (all powers below pyro are powerblocked by the reigning deity, the True Fire who got tired of how the Solarii were messing things up and, ah, fired them as managers) to test and experiment with objects and what happened when you heated them.
This led to steel, and carbon steel. It also led to steam engines heated by pyrokinesis.
However, without a mass base of power supply (only a few people have the combination of leisure caused by independent wealth, mental curiousity, strength of will to learn this difficult skill since the precursors are unavailable, and sheer luck to survive learning a very dangerous skill to learn Pyrokinesis) like water, wood, and coal provided in the Prime timeline, these technological advances never advanced to being more than rich men's toys.
This situation continued for several hundred years. Some of the advances provided by the pyrokinetics trickled down to most of society. Carbon steel plows were useful enough that nobles bought them for their peasants, and nobody wanted to send their soldiers into battle with swords that broke under the enemies' better quality swords. Some agriculture investment, some military weapons programs, a few medical advances, and entertainment for the upper nobility were the sum of the general advances.
One other advance was that systematic studies of pyrokinesis were undertaken. This led to schools of training, and pyro duels. This led to Rules of Pyro Combat, and that led to pyro combat training masters. A very quick, and fluid style of combat which emphasized dodging and misdirection as much as raw, ah, 'fire' power emerged. It did little good to throw a fireball at your opponent if he merely dove and rolled under it while flinging a smaller, but more precisely targetted fireball into your face.
For inspiration, think of Rennaissance fencing masters.
But, other, more battle heavy devices emerged from the laboratories of the alkemans. If one could form steel, and power steam engines, and pump up hydraulic rockets with steam pressure....why one could make a ten foot tall iron armor with two inch thick plates that was powered by steam and moved by pulleys. It could launch steam air pressure rockets with black powder explosives at its enemies. It could lurch across the battlescape as nearly invincible (unless it tripped).
And that is where we are now. The Kingdom of Albion, the Kingdom of Castille, the Kingdom of Gallia, and about a dozen other kingdoms are engaging in raids, and sponsoring pirates to raid each other, and assasinating enemies, and trying to put down peasant revolts....
Some of the people such as the Kingdom of Norte Frei which looks north to the Baltic Sea, and to some degree, the Albionese, are trying to follow the Pure Teachings of the True Fire. Others such as the Gallites, and the Roma Tribes have rejected the reformers of the Pure, and claim to be adherents to the corrupted classic doctrines, but in reality have embraced hedonism. This is proven by the massive waves of venereal disease common in the Roma, and by the tendency of the various Tribal States to have sudden changes of power orchestrated by an Alkeman pyro in an iron suit. The Albionese have resisted this tendency to coup d' etat via pyro as they claim its illegitamate for a ruler to be deposed by interior force. This has given them greater political stability, and ironically, the Albionese pyros are safer than the Roma pyros because no one thinks the Albionese pyros are about to grab for power tommorrow. In Roma, one is either a very tough pyro, or hidden, or dead.
Gallia is about halfway between Albion and Roma. Castile is hedonistic, but they are very strongly in favor of legitamate rulers.
=======================
And this gives us a world of skullduggery, deniable pirates sponsored by nations (like terrorists sponsored by nations today...how modern), galleons, and horsemen, sword fights, but also giant iron suits with rockets....Its early Rennaissance. Albion and Norte Frei are early Reformation, and hence a bit more advanced in freedom, morality, and science and generally successful than the Rennaisance States of the Roma Tribes and Gallia. Castille is kind of in the middle, although it definitely slants more toward the Rennaissance than the Reformation.