Arriving in midsummer of 77, Agricola finds that the Ordovices of north Wales have virtually destroyed the Roman cavalry stationed in their territory.

He immediately moves against them and defeats them.

He then moves north to the island of Mona (Anglesey), which had previously been reduced by Suetonius Paulinus in 61 but must have been regained by the Britons in the meantime, and forces its inhabitants to sue for peace.

The Welsh consider the Norwegians their liberators following the Norwegian victory against the Normans, but Magnus regards Anglesey as part of the Kingdom of the Isles and takes the island as a Norwegian possession.

Since the Norwegians never settle on the island, Anglesey reverts to Welsh control in 1099 when Gruffudd ap Cynan returns from Ireland.

The Norwegian control is at best nominal hereafter,but as Gruffudd awards Magnus with great rewards and honor, and during Magnus' second expedition in 1102 allows him to cut as much timber as he wanted, Magnus may possibly have reasserted the overlordship over Gruffudd formerly held by Godred Crovan, and thereby received the submission of Gwynedd.

The Governor Fenner, carrying emigrants to the United States, sinks off Holyhead (Wales), with the loss of one hundred and twenty-three lives, on February 20, 1841.