Complex sentence: A Medieval Cathedral was situated on the site prior to the 18th Century one but few traces of it are visible, this cathedral was damaged during the siege of Cork in 1689/90 when it came under fire from the nearby Elizabeth Fort.
Split into simpler sentences: A Medieval Cathedral was situated on the site prior to the 18th Century building, but few traces of it are visible. The cathedral was damaged during the siege of Cork in 1689/90, when it came under fire from the nearby Elizabeth Fort.