Title companies first started appearing in the United States in the late nineteenth century as a way to protect buyers against uncertainties about who really owned the land they were buying. In order to determine that the title being sold is “clear” that there’s no confusion or dispute about who actually has the right to sell it, the title company does what’s called a title search.
A title search is a record-by-record investigation of the ownership history of a specific parcel of land. The title company is looking for any irregularities in the record – they want to make sure it’s absolutely clear who owns this property, and that there are no competing claims or mitigating circumstances. They’re looking for any reason that a seller’s right of ownership could be challenged or complicated – any lien, or encumbrance. (An encumbrance is just a fancy legal way of saying anything that affects a title: mortgages, leases, easements, etc) Typically, they go as far back as they can. But usually, unless the law in a particular state says otherwise, searching records back 40-50 years is sufficient.