► History of the name Czechia
The name Czechia is absolutely not a new thought of present politicians. His most oldest documented records can be found in the file Jiří Barthold Pontanus of Breitenberk "Hymnorum sacrorum, beatissima de Maria Virgine et Patronis S. S. R. Bohaemiae, Libri Tres," Introducing the Virgin Mary and the Czech saints issued in Prague in 1602. Another document of the occurrence of this word is in the work "Respublica Boiema" by Czech writer Pavel Stránský [20], published in the Dutch town Leiden in 1634. A further reference is revealed in is the part no. XXXIII (in Act 3) "Aria. Allegro. En duplo sole Czechia" from the melodrama-oratorial musical composition Sub olea pacis et palma virtutis conspicua orbi regia Bohemiae Corona – Melodrama de Sancto Wenceslao (Under the olive tree of peace and palm tree of virtue the Crown of Bohemia splendidly shines the whole world – Melodrama of Saint Wenceslas), written by Czech Baroque composer Jan Dismas Zelenka in 1723. Similarly, in the case of the inscription on the base of the statue of St. Wenceslas in Libochovice from 1761, where the text "Vir Sactus Wenceslaus, Invictus Rex Czechiae Laureavit Leon Gloriosa" sounds in the same spirit (see detail of the inscription here). Generally, the name occurs very often in the baroque Latin.
Left: Page No. 204 of the book by Jíří Barthold Pontano with the chapter about St.John Nepomuk; right: the statue of St.Wenceslas in Libochovice from 1761
Another document of the occurrence of this word is in the work "Respublica Boiema" by Czech writer Pavel Stránský, published in the Dutch town Leiden in 1634. A further reference is revealed in is the part no. XXXIII (in Act 3) "Aria. Allegro. En duplo sole Czechia" from the melodrama-oratorial musical composition Sub olea pacis et palma virtutis conspicua orbi regia Bohemiae Corona – Melodrama de Sancto Wenceslao (Under the olive tree of peace and palm tree of virtue the Crown of Bohemia splendidly shines the whole world – Melodrama of Saint Wenceslas), written by Czech Baroque composer Jan Dismas Zelenka in 1723.
The oldest evidence of the English substantive word "Czech" in substantive (inhabitant, language) and and its adjective derivative (national) comes from 1840. The first historical record of using the word Czechia in English comes from the book by Henry and Thomas Rose "A New General Biographical Dictionary Projected and Partly Arranged" from 1841, another one we can find e.g. in the report about Prussian-Austrian war in Australian newspaper "The Mercury" from 23rd May, 1866 : where is written (see documents below).
Left: The first historical record of the name Czechia in English from 1841 -Henry and Thomas Rose: "A New General Biographical Dictionary Projected and Partly Arranged" ; right: The report from Prussian-Austrian war in Australian newspaper "The Mercury", May 23, 1866
The use of the name Czechia in North American press in 20's and 30's of 20th century was common. One for all examples comes from the article "Literary history of the Czechs", published on January 4, 1925 by The New York Times. The name is used there for the Czech state in historical context and is a reference to the Czech lands in its timeless national and geographical continuity (see the press cutting). This fact supports the assertion of Czech specialists to use this name for the Czech state in general, regardless of historical period or momentary political system: "...As Czechia can denominate our country in any historical period and in any social and political conditions..."
The article "Literary history of the Czechs" in The New York Times from January 4, 1925
In German, the oldest record of the equivalent one-word name, Tschechien, is from 1876, which was published in the book Bilder aus Böhmen, in Italian (Cechia) from 1927 (publication Rivista italiana di Praga) and in French (Tchéquie) from 1936.
It is evident that the name Czechia is not a neologism, as has been sometimes claimed, though previously unknown in English [23]. Former initial proposals for the Czech state: "Czechland" or "Czechlands", however linguistically correct, were rejected by experts as less proper from a historical point of view.
Names of the country, its territorial parts & their meanings
Source: https://www.czechia-initiative.com/czechia_name.html