My post on the Ancient Age can be found
here.
Although planning on a military victory from the start, I held off going to war until I could do so without having to cross the mountainous land bridge. In the meantime, I filled in the Viking peninsula, settling the corrupt south more sparsely. Except for Nidaros' granary, only barracks and half a dozen harbors were built. Given the centrality of Nidaros, I decided to build the FP later in the game, across the water and NW. Originally my cities had been garrisoned by warriors; now I built archers for home duty, and upgraded the warriors to swords.
In 430 BC I declared war on France, solely because they had captured the Lighthouse at Kiev from the Russians. Viking swordsmen took Kiev on the next turn, and proceeded to carve up the French with more landings up the coast.
In 310 BC, a Viking galley took advantage of the Lighthouse to make contact with the eastern hemisphere. The three eastern civs were all behind me in tech - China was at war with America and the Aztecs - but I was able to pick up monarchy as well as a lot of gold for my maps. After picking up 548g from the Kelts for monarchy, I went into revolt: seven turns!
The discovery of the New World: 310 BC
This wasn't the only bad news: my iron resource had dried up. In 210 BC I made peace with France, picking up two cities and leaving it only with Rheims as its capital. After transitioning into monarchy in 170 BC, I declared war on Russia in 110 BC. My swordsmen had been replenished and repositioned, and mostly encountered only spears and archers. In 70 BC I built a city atop the unconnected Russian iron, and upgraded my swords to MS as the Library gave me feudalism. These units then set about slowly taking the remaining Russian cities.
In the meantime, the home front had switched from building archers to horsemen. In 280 AD, just as the Greeks eliminated France, the Library gave me chivalry. My plan was to upgrade to knights and take out Greece, before going after England. The surprisingly slow AI research pace forced me to pursue engineering on my own, and I discovered it after 40 turns in 340. I then started researching invention at a research pace timed to coincide with the completion of a palace prebuild for Leo's.
In the meantime, I founded Drammen in 350 at the tip of the western American peninsula, and started work on a barracks. My home cities started building warriors again for garrison duty, because all 38 of my archers were sailing for Drammen as quickly as I could build galleys in my harbors. My goal was to have as many galloglasses (berserkers) as possible with ships to ferry them already in the eastern hemisphere as soon as I discovered invention.
In 360 I received my first leader finishing off the Russians and immediately declared war on Greece. Three turns later the FP was built in Thermopylae, which deprived the Greeks of iron. Just as I cleared the Greeks off the continent in 420, the Aztecs and Keltoi declared war on me. (The Keltoi were getting out of debt.) I promptly allied with China and America against the Aztecs, made peace with Greece, and allied with them against the Kelts.
I received Education in 450, ending the value of the Great Library. It had netted me only monotheism, fudalism and chivalry among the medieval techs I wanted. This, combined with the AI's traditional lack of gold early in the Middle Ages, kept me in a financial bind, balancing research for invention with a need to save gold for upgrades, while my luxury rate steadily decreased from 20 to 10%. (In the end, luxuries allowed me to keep it at zero, despite a total absence of happiness buildings or wonders.)
My knights captured southerly Mohacs and gained a leader - my first army - but bogged down against the Kelts. After cutting their iron resource in 520, I negotiated peace for 90g and 24gpt, as well as a RoP which allowed me to sit on their iron. I declared war on England and Greece two turns later. Striking from Kelt territory, I immediately cut off the English from their iron. England had its share of pikemen as well as Frankish axes, but my knight army led my mounted units to quick victories.
530 AD: 100 years before the invasion of the eastern hemisphere:
In 590, I finally discovered invention, then traded it to the Kelts for 105g and 40gpt. The next turn I completed Leo's, which launched my GA. It took me four more turns to upgrade all 38 of my archers and sail them for a devastating strike against the predominantly coastal Aztec cities. (Soon after I aggressively researched astronomy, and upgraded many of my galleys to caravels.) I attacked several cities in 650, and had the Aztecs on the ropes so quickly that I was able to declare war on America in 730. (I had assigned several trailing ships to pick off the outlying Aztec cities, and didn't worry about how long this took.)
My knights reduced England to its eastern island by 700, and in 740 I declared war against the Kelts. With a GA, my cities were building lots and lots of gallooglasses. Some sailed east to the other hemisphere, but others sailed up the channel to pick off the Keltic island and their more distant continental cities. My strategy was to slowly grind them down with a minimum of galloglass support, while my main effort went into a swift conquest of the eastern hemisphere. England was eliminated in 780, just before the GA ended, but the mopping up against the Kelts - pikes and longbows - continued for centuries, due both to culture flips and the low number of units assigned to this theater.
In 790 I traded for gunpowder, and confirmed to my relief that China had none. One turn later the Aztecs were wiped out, and I allied with China to help me eliminate the in-country American cities, as most of my captured cities were undefended, and I feared a stray American knight retaking a city here and there. China knocked out America in 830.
With the Kelts on life support, all my focus now shifted to China. Their army consisted mainly of pikemen and riders. Mao only had three inland cities - Beijing and the two American conquests - so I moved as many ships as possible off their coastal cities, while my galloglasses arrived outside the former American cities. My goal was to cripple China enough that the retaking of empty cities would be held to a minimum. I declared war in 890, and immediately took half of China (including cutting their iron). Now it was a race to position two armies plus support outside Beijing, pick off the flood of Chinese settlers, and transfer units among my ships to strike the remaining cities as quickly as possible. I suffered a few reversals - mainly because I didn't raze when I should have - but China and the last Kelt city all fell in 950, giving me a conquest victory.
950 AD: conquest and a view of the military
Most questionable about my strateg was choosing monarchy and letting the Great Library take me into the Middle Ages. The unusually slow AI tech pace kept me from reaching chivalry until 280 AD and invention until 590 AD. (The two hemispheres never made contact, and the Chinese never got past chemistry.) Corruption in a monarchy with no non-military improvements whatsoever kept my income low, so the timing of gold and research remained in concert, but could have come sooner with a more aggressive approach to research. The FP in 390 AD was a little late, but the reality was that there wasn't enough of a second (foreign) city core to make much of a difference. I could have built more settlers, but chose to focus strictly on units.
On the plus side, my decision to build (in order) warriors, archers, horsemen, and warriors again - until the GA made it possible to pump out the UU - worked out very well. The upgraded warriors took most of the continent, while I built horsemen which were in turn upgraded and took the Anglo-Kelt landmass. These rolling wars kept me active on at least two fronts at once, without ever finding myself too shorthanded. The kicker was shifting all of my archers to the eastern hemisphere before upgrading them, and having enough ships to wield them effectively. The AI's relative lack of cities, and their primarily coastal placement, made my decision to go all-out with the UU a successful one: the conquest of the eastern hemisphere in 300 years.
Edit: a couple of hours after finishing, I realized I could have conquered the easternn hemisphere even faster if I'd kept the upgraded UU's in the north where they were stationed - thereby attacking China first - and used reinforcements crossing the ocean further south to later hit the Aztecs, then finishing by hitting America from both sides. The Aztecs declaring war on me earlier distracted me from even considering this.