ˌɔn twˈɛnti ˈeɪt ˈeɪpɹəl wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd twˈɛlv, ðə tˈuː kˈɑːləniz wɜːɹ əfˈɪʃəli kəmbˈaɪnd, haʊˈɛvɚ wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd fˈɪftiːn ɪz jˈuːzd æz ˈɛnd dˈeɪt, bɪkˈʌz ðə ɹˌæɾɪfɪkˈeɪʃən ᵻlˈɪmᵻnˌeɪɾᵻd ðə lˈæst lˈiːɡəl ˈɑːbstəkəlz.
On 28 April 1812, the two colonies were officially combined, however 1815 is used as end date, because the ratification eliminated the last legal obstacles.