It was formed after Vidzeme and present-day Estonia (the western portion of the predecessor Diocese of Wenden) were conquered by Swedish king Gustav II Adolf.
The Diocese of Ikšķile was established in 1186 and designated a suffragan of the Metropolitan Archdiocese of Hamburg-Bremen by the Roman Pope Clement III on 1 October 1188.
[1] Renamed as Diocese of Riga in 1202 and promoted as Metropolitan Archdiocese of Riga on 20 January 1255[2] The Diocese of Wenden (Cēsis) was established within the territory of the Duchy of Livonia in 1582 by Polish king Stephen Báthory when this region came under the jurisdiction of the Polish–Lithuanian Commonwealth.
On 19 September 1684 the name of the diocese was formally changed from Wenden to Inflanty by Pope Innocent XI.
[5] From 1685 Catholic parishes in Semigallia (Zemgale) and the Diocese of Pilten in Courland were administered by the bishop of Inflanty (Polish Livonia).