Red Reading, PA Sep 5 cds and red "5" on 1848 cover to Pittsburg with manuscript "R" of the Reading "recorded" plan.

In the mid-1800s, concerns over the loss of valuable mail prompted the Post Office Department to introduce an official registration system on July 1, 1855, for a fee of five cents.

However, in the decade prior, an unofficial system for registering valuable letters was adopted at the Philadelphia post office from 1845 - 1854. The unofficial registration system spread from Philadelphia to other post offices throughout the country. Postmasters played a key role in this process, marking valuable letters with an "R" handstamp and recording their details. Although no fee was charged, these letters were tracked and handled with greater care.

This cover is an example of a manuscript "R" notation.