This mod allows yout to start your campaign in 1080, 1200, 1300, 1400, or 1500 and can be downloaded here:
http://www.twcenter.net/forums/downl...o=file&id=1820

1080

1) Two new factions; Serbia and the Cumans.
2) Most faction start out with more settlements.
3) Yes, the HRE is meant to be that big.

1200

1) Five new factions; Serbia, Cumans, Aragon, Bulgaria, and the Crusader States.
2) Slightly larger starting armies and some settlements are more developed.
3) Fight the Mongols in under 80 turns.

1300

1) Six new factions; Serbia, Golden Horde, Aragon, Bulgaria, Lithuania, and the Teutonic Order.
2) Much larger starting armies and most settlements have been improved.
3) Face the Black Plague, Timurids, and the rise of gunpowder weapons.

1400

1) Seven new factions; Serbia, Golden Horde, Aragon, Bulgaria, Lithuania, the Teutonic Order, and the Timurids. Milan is now playable.
2) Larger starting armies, though the plague has depopulated most cities.
3) Almost every weapon and unit is available (all units become available once America is discovered).

1500

1) Most of the smaller factions have been absorbed by larger factions.
2) Larger starting armies, mostly gunpowder units and pikemen.
3) All weapons and units are available and most can be recruited.
4) Some new events will occur, though they have no impact on the game.

Conquest vs Achievement

One of the main features of this mod is that the player can choose whether their win conditions will be based on Conquest or Achievment. A Conquest campaigns is won if the player takes a set number of settlements from anywhere on the map, while an Achievement campaign requires the player to defeat certain factions but does not require the player's faction to possess more than one settlement. To access this feature on the campaign screen you need to click where the 'Long / Short' campaign button was.

Total War Eras Installation Guide

1) Go to the Medieval II Total War directory (default is C:\Program Files\SEGA\Medieval II Total War).

2) Paste the eras.bat, eras.cfg, and 'eras' folder into the Medieval II Total War directory. These files form the basics of the game.

3) Paste the vanilla 'data' folder into the Medieval II Total War directory, you will be asked if you wish to overwrite it, click yes. This will install the shared.sd and strategy.sd in the 'data\ui' folder. These files are needed to make the banners work but may prevent other mods from working. If you have a problem with other mods try deleting them (there's a spare copy of them in the 'seasons\data\ui' folder).

4) To play this mod double click on the 'eras.bat' file (you can make this file into a desktop shortcut).

How to Play

0) Download the mod
1) Start up this mod by clicking on the eras.bat.
2) Click on 'Single Player' option in the start menu.
3) Click on 'Custom Campaign' on the next menu.
4) Choose which campaign you want to play.
5) Select a faction and start this mod.

Additional Files

To fully enable the sound copy the 'data/sounds/events.dat' and 'data/sounds/events.idx' files to the 'eras/data' folder.

Other mods
The following mod were added to this mod with the permission of their respective authors.

Armoured Generals Mod, Vanilla Style Skins 1.0, Teutonic Campaign Skinpack (Tyre) :
http://www.twcenter.net/forums/showthread.php?t=106633

Banner & Symbol MOD (joedreck) :
http://www.twcenter.net/forums/showthread.php?t=93253

Big Map 1.06 (Big Map): increases the number of provinces to 166 and increases the number of resources to 436.[http://www.totalwarmods.com/BigMap%20Download%20Page.html]

Blood, Broads, & Bastards v2.1 (dearmad) : gives factions generals and leader more traits
http://www.twcenter.net/forums/downl...do=file&id=955

Bringing Justice to the Horde! (Kalos) : reskins Mongols
http://www.twcenter.net/forums/downl...o=file&id=1651

burrek's Unique Europeans, Early Period v0.91 (burrek): reskins most European factions' early units
http://www.twcenter.net/forums/downl...o=file&id=1025

burrek's Unique Europeans, High Period v0.3 (burrek): reskins most European factions' late units
http://www.twcenter.net/forums/downl...o=file&id=1048

Byg's Grim Reality 2.0 (Byg): character and supply traits (soldiers may munity if you spend too long in enemy terriory). (http://twcenter.net/forums/showthread.php?t=106060)

Byzantium Armor Progression Mod V 0.7 (WhiteWolf) :
http://www.twcenter.net/forums/downl...o=file&id=1134

Highways mod (selenius4tsd): add highways (http://www.twcenter.net/forums/downl...o=file&id=1125)

New Garrison Script (GrnEyedDvl): an AI settlement with a Governor will now recruit mercenaries when it's being sieged. (http://www.twcenter.net/forums/downl...o=file&id=1522)

Ornamentum 1.32 (GubZol and DaNova) : reskins England, Scotland, and Denmark
http://www.twcenter.net/forums/showthread.php?t=136437

Realistic Walls and Siege Engines for UAI 1.6 (Raptor_341):
http://www.twcenter.net/forums/downl...o=file&id=1728

Teutonic Campaign Skinpack (Tyre) : changes the appearence of Teutonic, Lithuanian, and HRE units http://www.twcenter.net/forums/showthread.php?t=106633

The Real People Mod (Matz) : gives all agents more traits
http://www.twcenter.net/forums/downl...o=file&id=1809

Turk Reskin 1.1 (Eternal Cocoon): reskins Turks
http://www.twcenter.net/forums/downl...o=file&id=1044

Ultimate Battle AI 1.2 (GrandViZ): improves AI's fighting ability, conduct during sieges, and unit formation. (http://www.twcenter.net/forums/downl...o=file&id=1602)

Ultimate AI Mod 1.6 (GrandViZ): improves AI's behaviour in campaign mod, diplomacy, and unit's attack. (http://www.twcenter.net/forums/downl...o=file&id=1643)

Vanilla Style Skins 1.0 (Tyre) : changes the appreance of English, Scottish, and HRE units
http://www.twcenter.net/forums/showthread.php?t=106633

Also I'd like to thank dave scarface for making a descr_events.txt file that works with the Big Map mod.

Known issues

I am aware of the following problems and I am working on a way to fix them.

1) If you choose one of my Campaigns on the Custom Campaign menu; then go back to the custom campaign menu, rather than selecting a faction and starting this mod then this mod will crash.

2) If you click on several factions, rather than just choosing one and starting the game, the mod will crash (to counter this choose the faction you want to play first, then start the game).

Future Improvements

I plan to add a 10th century start point and some more factions.