| Year | Events | No. of archdeaconries at end of year |
|---|
| Ancient foundations (c. 1050–1250) | Anglesey,Bangor andMerioneth in Bangor Diocese;Llandaff in Llandaff Diocese;St Asaph in St Asaph Diocese;Brecon,Cardigan,Carmarthen andSt Davids in St Davids Diocese | 9 |
| 1844 | Monmouth created in Llandaff Diocese;Montgomery created in St Asaph Diocese;Anglesey (Bangor Diocese) discontinued;Bangor (Bangor Diocese) renamedBangor & Anglesey | 10 |
| 1890 | Wrexham created in St Asaph Diocese | 11 |
| 1921 | Monmouth transferred from Llandaff to the new Monmouth Diocese | |
| 1923 | Brecon transferred from St Davids to the new Swansea & Brecon Diocese;Gower created in Swansea & Brecon Diocese | 12 |
| 1930 | Newport created in Monmouth Diocese | 13 |
| 1948 | Margam created in Llandaff Diocese | 14 |
| 2002 | Morgannwg created in Llandaff Diocese | 15 |
| 2018 | Gwent Valleys created in Monmouth Diocese;Anglesey (re-)created in Bangor Diocese;Bangor & Anglesey (Bangor Diocese) renamedBangor | 17 |
| 2020 | Morgannwg (Llandaff Diocese) discontinued | 16 |