Siasau, a name that was considered to be myth in where two brothers immigrated from Samoa to Tonga, named Sia and Sau. The two brothers were both twins, but the other was sickly. The sickly brother wanted to ensure that his name was to be carried on with his twin brother to become known as SIASAU.Later, when the sickly brother had died, the name SIASAU was carried on by his surviving brother to the lands of Tonga, where he settled. After some time settling in Tonga, many of SIASAU's descendants had migrated across the oceans back to their fatherland, Samoa, Hawaii and other neighbouring lands.Thus the family name flourished among the lands for the many generations. As for the present generation, they too inherited the name SIASAU dating back to earliest known person named Visesio Poasi Siasau, father of Tivoa Siasau.