During the 6th Century, for reasons which are still unclear, the Anglo-Saxon consonant cluster "sk" changed to "sh", so that skield became shield. This change affected all "sk" words in the language at that time, whether recent borrowings from Latin (e.g. disk became dish) or ancient aboriginal borrowings (e.g. skip became ship). Any modern English words which make use of the "sk" cluster came into the language after the 6th Century (i.e. after the sound change had ceased to operate), mainly, as we will see below, from Scandinavia.