(predator)
Going for conquest. Not that this seemed like a smart goal as the map unfolded
Link to Ancient Age spoiler
Entering the Middle Ages
At 610BC I'd met Egypt, Persia, and China on the other continent. My world looked like this:
At this date Persia entered the Middle Ages so I traded to do so too. My free tech was Monotheism. Persia's was Engineering. I gifted Babylon forward and she also got Engineering. I'd intended to gift Babylon and Byzantines forward but at this point stopped and reconsidered. There seemed no point hurrying another Civ forward. Babylon and Byzantines would be researching Feudalism. I had no need of it - didn't have iron, didn't have horses, Feudalism wouldn't help me nor would Chivalry. So why hurry the tech pace? I traded for Engineering and left it at that.
I continued research of Literature, getting it in 530BC. Then I flipped some prebuilds and also used cash to rush libraries. I did this because I expected I'd be doing more research and I also wanted to gain culture, both for holding towns in the long term and for squeezing Babylon and Egypt in the short term. This seemed a good way to leverage Sumeria's scientific advantage.
The Resource Problem
The resource problem was very much on my mind. I wanted iron and wanted horses but didn't know how best to get them. I didn't want to defer the problem until Cavalry because that might just trade my iron problem for a saltpeter problem.
I decided to pursue three options at once:
1) I'd discovered iron near the coast north of Babylon and some horses a bit inland from there. Claiming them was chancy - if I sent units too soon they could die at the hands of barbarians. After a while Babylon and Byzantines would probably subdue most barbarians but if I waited too long then they'd also claim the resources. I decided to send boats with a couple of settlers and some Enkidus a few turns after entering the Middle Ages. With luck my rivals would have dealt with the barbarians by the time I arrived and I'd still be soon enough to claim the resources. Worth trying but a gamble, not a sure thing.
2) After Literature I'd research toward Astronomy so that I could trade with the other continent. My rivals would almost certainly be researching on the Feudalism -> Invention -> Gunpowder path so this approach would also give me something useful to trade.
3) After libraries I'd start building some military. Barracks and then Archers to later become Longbowmen. If I got iron and Feudalism then I'd also build Medieval Infantry. Either way I'd begin building a force which could if necessary push through Babylon to reach the resources.
In 430BC my units landed beside the iron and I was able to settle there. There were enough barbarians in the area that I didn't dare send my second settler inland for the horses yet. He stayed in the coastal iron town along with his two Enkidu defenders. In 350BC Babylon settled beside the horses. I hoped to still get them via a culture squeeze. In 250BC I finally decided to risk the journey and sent my settler out from the iron town. In 150BC he settled, the next turn I rushed a library, and in 110BC I had horses within my borders:
Of course it would be some time before I had those horses connected. But I was just two turns from connecting (roading) the iron at this point.
In the meantime I'd learned Theology, traded for Feudalism, and was two turns from learning Education.
I'd also built Barracks in most of my core cities. I'd only just begun archer production.
I'd also completed my Forbidden Palace, in a city inside the mountain/volcano ring east of the capital. And had met Mongols and Japan, completing my contacts with other Civs.
War with Babylon
In 30BC, two turns after I connected iron, Babylon surprise attacked me. She triggered my Golden Age and didn't capture anything.
This was sooner than I wanted war. I'd hoped to build up a force of Knights and then attack Babylon. I had just 2 archers and 1 MI at this point.
The attack cut off my supply of iron since Babylon had a number of coastal towns between my core and my iron town. So I'd have to revert to plan 3 (Longbowmen - by this time I'd traded for Invention) for my initial fighting.
I immediately bought an alliance against Babylon from the Byzantines and started rushing military production.
I held back while building up forces. Byzantines kept the Babylonians engaged so that they didn't have time to invade me. In 50AD I started advancing with 6 MIs (from production started before I lost my iron connection) and 6 Longbows. I took the first coastal town in 90AD. Because I had Astronomy by then this resulted in connecting my iron and horses (had finished a road to horses) to the core. I immediately switched military production to Knights. Soon after this I lost my iron and horse connection again due to another Babylon city expanding its borders to the ocean. But I did have some Knights already in production.
Despite being at war on two fronts Babylon was a strong opponent. I presume she also had a Golden Age.
Research on the other continent had been proceeding quickly. In 50AD I traded for Gunpowder and saw that I had saltpeter available. At that point I decided to try for an edge in technology and to storm my rivals with Cavalry. I continued invading Babylon at a conservative pace while researching as quickly as I could toward Military Tradition.
The war with Babylon see-sawed a bit. I reconnected my resources, lost them again when Babylon recaptured a city, then took the city again. Overall I made progress. I captured her capital in 230AD and with it the Pyramids, an especially nice prize. Byzantines dropped out of the war in 250AD. I got two leaders during the war and set them both aside as empty armies to be filled later with Cavalry.
I learned Chemistry in 150AD, Metallurgy in 250AD, and Military Tradition in 300AD.
In 320AD I gave Babylon peace for 5 of her remaining 8 towns and my world looked like this:
War weariness had gotten quite bad; it was nice to be able to drop my luxury rate from 50% to 20% after making peace.
During this war the Egyptian town on the northeast coast of my home region had flipped to me.
Military status: At the end of the Babylon war I had 31 Cavalry, 6 of them in two armies. Also 3 remaining elite Knights and 2 surviving Longbows.
Slowing the Pace
I wanted the Civs on the second continent to be constantly at war. I.e. every Civ there to be actively at war with at least one neighbor at any given time. That would slow their research (giving me a better chance to attack them with Cavalry at an advantage), would use up some of their Golden Ages, and would keep them a bit weaker.
I didn't have to meddle much to make that happen. The remote Civs were already fighting a fair bit when I first met them. During the Babylon war I only got involved once. Japan was at peace with everyone so I declared on her and allied Egypt. Soon after China was also at war with Japan without me having to bribe her.
I sold my tech lead slowly, squeezing out good deals. Persia was the strongest remote Civ and I was able to siphon off a good bit of her income. E.g. in 270AD I got 143gpt from her for Chemistry.
War on Byzantines
In 340AD I declared on Byzantines and attacked.
I sent my two armies deep into her territory to find and take her city with the Great Wall. They found it immediately and took it in 350AD.
I also sent in a settler at the start, founding a new town just inside Byzantine territory and rushing barracks there. Despite all my libraries Byzantines had a small culture lead. I didn't want to risk healing troops in captured towns. My new town near the border provided a place for troops to retreat and heal quickly.
It was tough slugging even with Cavalry on my side and with them presumably weakened by their previous fighting with Babylon. They had a lot of units, including many Pikemen and Musketmen defenders.
I lost quite a few units and one of my armies. But my forces were stronger and prevailed. In 450AD I took their last town and eliminated Byzantines:
I'd done no research during this war. Almost all funds had gone toward rushing military units. At the end of the war I had 40 Cavalry and 2 remaining elite Knights.
I got a third leader early in this war. He built an army which I loaded with just 2 Cavalry. I used it only for easy kills, saving it to sail to the other continent later on. (Vs. filling it with 3 Cavalry - if I did that it wouldn't be able to travel in a Caravel.)
During the Byzantine war I gave Japan peace in exchange for an island town.
War on Persia
Persia seemed like the easiest starting point for invading the other continent.
Invading Persia would cut off trade routes with the other Civs. And luxuries were very important - I was fighting a lot in Republic and using the luxury slider. Every time I notched it up that meant less funds available for rushing military units. Between this factor and my desire to have everyone's maps I decided to learn Navigation while repositioning my troops to invade Persia.
In 490AD I learned Navigation, traded for everyone's maps, then declared on Persia. China was already at war with her. I bought alliances from Mongols and Japan.
I waited two turns for Persia's military to engage with Mongols and Japan, then landed my troops in 510AD at two points on Persia's coast. Each invasion group included a settler to establish a safe town for healing. In 520AD each group settled its beachhead, rushed a barracks, and captured some nearby towns. A nice first turn which included gaining ivory:
By this time I was well ahead of all remaining Civs in culture. Still I expected an occasional flip and wasn't going to risk losing much. Troops returned to my coastal towns to heal. After the first turn of taking a town I would leave just one fortified Cavalry - in the town to avoid leaving a cheap target if it was close to the border, nearby but outside the town if not near a border.
After my initial onslaught progress slowed. Persia managed to field a good number of units (Immortals of course) despite being at war on three fronts.
I ferried new troops from home and rushed new troops locally with gold.
In 590AD I took her last town and eliminated Persia. At this point I had 60 Cavalry and one remaining elite Knight. Had five owned luxuries and two imported.
Swatting Babylon and Egypt
My peace with Babylon had expired and during the invasion of Persia I decided to finish her off. She had four towns on the home continent and one on the north central island.
I declared in 560AD and got my 4th leader on the home continent while attacking Babylon. He formed an army and made the long trip to Persia where he'd be useful.
In 610AD I eliminated Babylon.
Egypt was another minor power. Her long wars with many other Civs had reduced her to four towns - one east of Persia and three in my northern region. In 600AD I declared on her. In 620AD I had all four of those towns and she was out of the game.
Islands
After learning Navigation and trading for maps I saw six occupied islands in the world. And I discovered a seventh shortly after. These islands presented an extra challenge to a fast conquest.
I had a presence on 3 islands: The small southwest one due to taking it from Byzantines. The large north central one due to a town received from Babylon for peace. The small northeast island due to a town received from Japan for peace.
I rushed harbors, barracks, and military units on the two northern islands.
On the north central island I took a city each from Babylon and Persia during my wars on them. My rivals had reduced China to a single town which was on this island. In 630AD I declared on China, took that town, and that was it for China. She was out of the game.
I sent a settler and some Cavalry to the small southeast island which I'd discovered. I was able to claim that island without fighting for it.
That left three other islands to deal with. A largish south central one where Japan had a feeble foothold, a small north central one shared by Japan and Mongols, and a large one just off Japan's coast containing four Japanese towns and a lot of jungle. I dispatched Caravels with settlers and Cavalry to each of these islands in the mid 500s. This and ongoing rushing of units on two of the other islands put a considerable dent in my funds in this game. I'd have liked to use those funds in my primary invasions but didn't dare leave the islands till the end - if I left them, or didn't have sufficient strength at any one point, my conquest date would be delayed while most of my military was idle and a bit of it went traveling to root out some final outpost. So I spread my forces out somewhat wastefully to take everything at once, this seemed the lesser of evils.
The Final War - Mongols and Japan
Most rivals sure were strong in this game. They'd built up like deity AIs. Despite my technology lead and keeping them at war each rival required careful handling.
An interesting example in 600AD: The Mongols were my next target. They had one largish stack returning home from their war on the now defunct Persians which was traveling through mountains. I'd incur significant losses if I attacked it directly in the next few turns. I was repositioning and healing units and had some to spare this turn. So they surrounded the Mongol stack leaving just one exit onto a floodplain tile east:
In 620AD the Mongol stack had moved to the floodplains. I declared on Mongols and attacked, including immediately wiping out that now vulnerable stack.
I allied Japan against the Mongols, paying for it up front since I did not plan to stay at peace with Japan for 20 turns.
In 670AD the Mongols were down to 7 cities and I declared on Japan.
There was nothing special during these final wars, just a lot of fighting. I got 3 more leaders. They all formed armies. Armies were invaluable in leading attacks deep into enemy lands and assaulting fortified positions. I lost one army in these wars - got too aggressive when I should have let it heal completely before fighting again.
Japan seemed to have great RNG luck attacking and defending. Her Samurai's good defense didn't help me of course. Nor did her Sun Tzu's and Knights Templar wonders.
In 730AD I eliminated Mongols:
Japan had 11 towns left. Three of those towns were on the large island. I had the other six islands in the world under control.
At this date I had 73 Cavalry but many of them were at defensive points (particularly all the islands) or in transit (mostly to the large island at this date.)
I was 43 tiles from domination. I hadn't been rushing toward domination but had been keeping almost everything I captured and had been filling in land when convenient. From this date on I had to be careful to avoid accidental domination.
In 750AD I took the last of Japan's cities on the island. She was down to 5 northern towns. I might have finished a turn faster if I'd sent boats along the north coast instead of my troops having to slug through the tundra.
In 780AD I took the last of them getting a 790AD conquest victory.
Re finishing in the Middle Ages: At the end of the game no one had even learned Physics!