Who were the earliest settlers of the Gilbert Islands and Banaba?

The earliest settlers of the Gilbert Islands and Banaba arrived from Southeast Asia by way of Micronesia approximately 4,000 to 5,000 years ago.12

Later, around the 14th century CE, the southern islands experienced an influx of Samoans, which subsequently led the islanders to adopt a gerontocratic style of government based on rule by elders.12