Albion layouts

Albion is the layout query people type most specifically: Celtic city versus Roman city. The companion library has both lines. A swamp tile is not buildable until Drainage is researched, and the ditch in the published blocks connects on the north side while the road joins on the south.

Two cultures, not one grid

Tier 1 is shared. Tier 2 Roman files come in an early version without a fanum and a later version with it. Celtic Tier 2 is its own advanced file. Picking Mercator (Roman) or Smith (Celtic) locks the other branch until tier 3, so a Roman housing stamp will not satisfy a Celtic island and the reverse is also true.

Marsh and dirt

Eel farms sit on drained marsh. Bread has a rectangular basic file and an advanced one. Amphorae have an advanced file. Dirt itself is pulled from marshland, which is why the stamps usually leave the dirt building out and expect you to supply it from outside the block.

I do not have a single official table of every Celtic building versus every Roman one. The split above is assembled from the layout filenames and from the campaign note about the tier-2 lock. That is two sources, not a developer spreadsheet.