Only the closest 16 castles within a 20 squares radius surrounding a shrine can get enlightened, with the following exclusions:
- Cities with a place that is currently being built or upgraded
- Cities with a lvl 10 palace
- Cities that has a palace of another shrine
- Cities of a player that does not belong in an alliance
- City that just got enlightened by that shrine
EnlightenmentScore = CityScore / (DistanceToShrine + 2)
This means that higher City Score and the shorter Distance to Shrine gets bigger chance of enlightenment.
To win LOU, you need one level 10 palace. So you need a chosen city to get lit over and over again, (provided that you already have enough faith.) (On a side note, it is better to build many low level palaces for faith then a few higher level palaces.)
To reduce the chance of enlightenment of other castles around the chosen castle, you have to reduce their score to as low as 7. What we did was castled 16 cities around the shrine, and flattened it with cats/rams. These castles, even when closer, has next to zero chance of enlightenment. The palace right below it was locked before the March update, so it doesn't count. The result was amazing. The chosen palace got enlightened every other time and we were able to build lvl 10 palace.