Help:How do I merge double items?
Creating Items or importing Items from another database bears the risk of creating doublets, i.e. Items of the same thing with different Q-Numbers. These are particularly obnoxious since they will create forks of information attracting statements that ar no longer aggregated and checked against each other.
How to use MergeItems to unite Items
If you find Items on the same object you can merge them with the MergeItems link in the Menu. The merging has to be prepared though. You will have to decide which Item you want to resolve and which Item you want to become the receiving Item of all the information — that is the second in the tool's input box.
It is advisable to first check which of the two items has more links referring to it — that should become the receiving item, because it will require less changes of links that are already referring o the Item.
The receiving Item should get the better name (use the alias input field to state the name variants). You will then have to make sure that you do not create a conflict of descriptions in any of the languages. Blank the descriptions which you want to get rid of and revise the descriptions you want to keep. You can now merge the two items (unless they have no Property conflicts - such as conflicting statements of succession).
After merging check the receiving Item to make sure that the aggregated information looks good.
The item which you have resolved might still be addressed in other Items. Use the "What links here" tool in the menue to get the list of the links that need to be corrected, and change the entries to the preferred Q-Number. This is not vitally necessary since the software will fetch information from the Item referred to in the individual links, but it creates better SPARQL searches, since these searches will from now onwards refer to a Q-Number without title (and with a redirect once you click the respective link).