Name Abbreviations

This weekend Taggart, Liz, Amber and I visited the San Antonio museum of art. Afterward we wandered around downtown for a bit, looking for coffee. One of the things in the skyline there is the Hotel Robt E. Lee. I had forgotten how names are sometimes abbreviated and we thought up some other names that can be abbreviated. Robert, Thomas, Charles, William, hmm, what else? This is different from names with a diminutive or shortened version. "Robt" is an abbreviation; "Bob" is a shortened version and "Bobby is a diminutive. Where and why did name abbreviations develop and why?