Henry II attended the Christmas service at the cathedral in 1171, and in the years thereafter, Strongbow and other Anglo-Norman magnates helped to fund a complete rebuilding of Christ Church, comprising the construction of a choir, choir aisles and transepts, the crypt, and chapels to St. Edmund and St. Mary and St. Lo. A chapel to St. Laurence O'Toole was added in the 1200's and much of the extant nave was built in the 1230's. In 1300 Archbishop Ferings of Dublin arranged an agreement between the two cathedrals, the Pacis Compostio, which acknowledged both as cathedrals and made some provision to accommodate their shared status (see below for more on this). By 1358, the nave of the cathedral was partly in use for secular purposes, and a "long quire" was added, extending the old choir area by around 10 metres. The cathedral was the location of the coronation of Lambert Simnel in 1487 as 'King Edward VI' a boy pretender who sought unsuccessfully to depose Henry VII of England. In 1493, the Choir School was founded.

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