In the early 20th century, the criteria of being a provincial municipality, as stated in Laws on the City Formation (市組織法), included being the provincial capital as well as having a population of over 200,000, or over 100,000 if the city had a particular significance in politics, economics and culture. After moving to Taiwan, where many cities considered to be insignificant had large populations, the Republic of China government raised the limit to 500,000 in 1981 in the Scheme on the Local Rules in Various Counties and Cities of Taiwan Province (臺灣省各縣市實施地方自治綱要). It was later raised again to 600,000.
There were originally four more: Taipei and Kaohsiung were upgraded to direct-controlled municipalities, while Changhua and Pingtung were lowered to county-controlled cities. Chiayi and Hsinchu were temporarily lowered to county-controlled cities as well until 1982.
Carana formed a city peopled by the inhabitants of the surrounding country, and whose era was dated from this event.
The town was organized like all the provincialcities; it worshiped the emperors; with some adjacent towns it formed a conventus of which the capital was Neocaesarea; it had coins dating from Trajan.
Adrian visited the city in 124; under this prince and his successors its beauty was increased by the erection of new edifices, a stadium, a portico, a gymnasium, and temples; the principal god was Hercules, whence its surname Heracleopolis.