Parchment letters sent, sealed, in reply to royal writs summoning peers to Parliament. The letters sought to excuse their sender from attendance, and usually to name a proxy to act on behalf of the sender. Nearly all the letters are from spiritual peers: archbishops, bishops, abbots, priors or occasionally chapters, deans and archdeacons. Few seals remain, and most of them are fragmentary.
The series derives initially from a special collection in the Tower of London known in 1832 as 'Royal Letters, etc', and started in the previous century as the most significant, historically speaking, of the public records. Most of the rest of the series comes from discrete regnal bundles of proxies kept in the White Tower until 1856 with Chancery records. Additions were made to the series as it was being filed in the 1890s, by which time the so called Royal Letters had been broken up in favour of more manageable Special Collections and additional Chancery series.