For those who do not understand Afrikaans, here is a translation of Ronel's answer:
"In 1840, the first Voortrekker State was established on Potchefstroom with an agreement between Hendrik Potgieter and Andries Pretorius, which was called the Republic of Natalia and included Transvaal, Northern Free State and Natal. Then the Voortrekker Church was also founded, which included the congregations of Potchefstroom, Winburg and Pietermaritzburg. On 16 January 1841, the Volksraad appointed the first church councils for the congregations and the Presbyterian missionary from America, Rev. Daniel Lindley, was appointed as the first pastor of this Voortrekker church.
"Rev. Lindley lived in Natal and in March 1842 on his way to Potchefstroom also visited Winburg, confirmed the first church council members, held services in the various wards of this extensive congregation and administered the sacraments. This is also where the baptism and membership registers of the congregation began. With this first visit, Rev. Lindley 331 children baptised here.
"So I think we can safely place the baptisms under Natalia Republic, but I suggest an explanation in the Biography to explain the place name (history) might be a good idea since the baptism registers are now being preserved in the Transvaal and Free State's Church Archives and can cause a lot of confusion."