LETTERS PATENT. — This term is used, in contrast to *litterae clausae*, to denote those public documents drawn up in a different and simpler form than charters (*privilegi*, q.v.), which were sent or delivered to the addressee without any sealing.
They are far more numerous than sealed letters, which only began to come into widespread use at the end of the 12th century. The sealing of these latter was done by means of a seal affixed to a cord or a strip of parchment wrapped around the document.
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BIBL.:** A. Giry, *Manuel de diplomatique*, Paris 1894, pp. 755–780 and 797–798; H. Bresslau, *Handbuch der Urkundenlehre*, I, 2nd ed., Leipzig 1912, pp. 65–67; A. de Bouard, *Manuel de diplomatique française et pontificale*, I, Paris 1929, pp. 55–56.