In the fictional history of Middle-earth, the original Certhas was created by the Sindar (or Grey Elves) for their language, Sindarin.

The division between the older Cirth of Daeron and their adaptation by Dwarves and Men has been interpreted as a parallel drawn by Tolkien to the development of the Fuþorc to the Younger Fuþark.

[1] The original Elvish Cirth "as supposed products of a superior culture" are focused on logical arrangement and a close connection between form and value whereas the adaptations by mortal races introduced irregularities.

[2] In the Appendix E to The Return of the King, Tolkien writes that the Sindar of Beleriand first developed an alphabet for their language some time between the invention of the Tengwar by Fëanor (YT 1250) and the introduction thereof to Middle-earth by the Exiled Noldor at the beginning of the First Age.

[3] This alphabet was devised to represent only the sounds of their Sindarin language and its letters were mostly used for inscribing names or brief memorials on wood, stone or metal, hence their angular shapes and straight lines.

[4] An abecedarium of cirth, consisting of the runes listed in due order, was commonly known as Certhas ([ˈkɛrθɑs], meaning "rune-rows" in Sindarin and loosely translated as "runic alphabet"[5]).

In Beleriand, before the end of the First Age, the Certhas was rearranged and further developed, partly under the influence of the Tengwar introduced by the Noldor.

This reorganisation of the Cirth was commonly attributed to the Elf Daeron, minstrel and loremaster of King Thingol of Doriath.

After the Tengwar became the sole script used for writing, the Angerthas Daeron was essentially relegated to carved inscriptions.

Note: In this article, the runes of the Angerthas come with the same peculiar transliteration used by Tolkien in the Appendix E, which differs from the (Latin) spelling of both Quenya and Sindarin.

As the Dwarves of Erebor would trade with the Men of the nearby towns of Dale and Lake-town, they needed a script to write in Westron (the lingua franca of Middle-earth, usually rendered in English by Tolkien in his works).

[20] These runes are basically the same found in Fuþorc, but their sound may change according to their position, just like the letters of the Latin script: the writing mode used by Tolkien is, in this case, mainly orthographic.

Nevertheless, they are known to us from a slip of paper that Tolkien wrote; his son Christopher sent a photocopy of it to Paul Nolan Hyde in February 1992.

[23] The system was reanalyzed by Carl F. Hostetter, who corrected the reading of the χ̑ rune to an ich-laut (voiceless palatal fricative).

The three characters represent the English ⟨k⟩, ⟨oo⟩ and ⟨sh⟩ graphemes, as follows: A formal Unicode proposal to encode Cirth as a separate script was made in September 1997 by Michael Everson.

[30] Two different layouts are defined by the CSUR/UCSUR: Without proper rendering support, you may see question marks, boxes, or other symbols below instead of Cirth.