According to Sugar Help ...

When merging duplicates, "... before the duplicate records are deleted, related information such as activities, history, contacts are moved from the duplicate records to the primary record."

Likewise,

When converting a (in this case) Lead to a Contact, "... Sugar creates a new contact, associates it with the related records and displays links to the new records. You can also view these records from the contact’s Detail View."

Question: What happens to the Campaign history records that are associated with the Target, Lead, or Contact that is being converted or merged?

--Gerry