I'm definetly sure this is not suppoused to happen, I have in a map that I want, two civs with the same name and the exact same name for the starting city. They have different (though similar) histories. It's the Merged Cities group.
Edit: Geh, tried doing an alternate history, but they are still there. I wanted that map
Created in DF v0.28.181.40d11.
[WORLD_GEN]
[TITLE:LARGE]
[SEED:905933048]
[HISTORY_SEED:1350785763]
[NAME_SEED:1596748831]
[DIM:257:257]
[END_YEAR:1050]
[BEAST_END_YEAR:300:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:1]
[ELEVATION:1:400:1600:1600]
[RAINFALL:0:100:400:400]
[TEMPERATURE:40:90:400:400]
[DRAINAGE:0:100:400:400]
[VOLCANISM:0:100:700:700]
[SAVAGERY:0:100:400:400]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[GOOD_SQ_COUNTS:150:1500:3000]
[EVIL_SQ_COUNTS:25:250:1000]
[PEAK_NUMBER_MIN:50]
[OCEAN_EDGE_MIN:2]
[VOLCANO_MIN:180]
[REGION_COUNTS:SWAMP:1032:7:6]
[REGION_COUNTS:DESERT:1032:7:6]
[REGION_COUNTS:FOREST:4128:13:12]
[REGION_COUNTS:MOUNTAINS:8256:9:9]
[REGION_COUNTS:OCEAN:8256:7:6]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:6000:13:12]
[REGION_COUNTS:HILLS:7256:13:12]
[EROSION_CYCLE_COUNT:250]
[RIVER_MINS:600:600]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:3000]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:50]
[MOUNTAIN_CAVE_MIN:100]
[NON_MOUNTAIN_CAVE_MIN:200]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_RIVER:2]
[SHOW_EMBARK_POOL:2]
[SHOW_EMBARK_M_POOL:2]
[SHOW_EMBARK_M_PIPE:2]
[SHOW_EMBARK_CHASM:2]
[SHOW_EMBARK_PIT:2]
[SHOW_EMBARK_OTHER:2]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:50]
[TOTAL_CIV_POPULATION:20000]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:8256:16512:8256]
[RAIN_RANGES:8256:16512:8256]
[DRAINAGE_RANGES:8256:16512:8256]
[SAVAGERY_RANGES:8256:16512:8256]
[VOLCANISM_RANGES:8256:16512:8256]