Standard Croatian is based on the most widespread dialect of Serbo-Croatian, Shtokavian, more specifically on Eastern Herzegovinian, which is also the basis of Standard Serbian, Bosnian, and Montenegrin. In the mid-18th century, the first attempts to provide a Croatian literary standard began on the basis of the Neo-Shtokavian dialect that served as a supraregional lingua franca pushing back regional Chakavian, Kajkavian, and Shtokavian vernaculars. The decisive role was played by Croatian Vukovians, who cemented the usage of Ijekavian Neo-Shtokavian as the literary standard in the late 19th and the beginning of the 20th century, in addition to designing a phonological orthography. Croatian is written in Gaj's Latin alphabet.
Besides the Shtokavian dialect, on which Standard Croatian is based, there are two other main dialects spoken on the territory of Croatia, Chakavian and Kajkavian. These dialects, and the four national standards, are usually subsumed under the term "Serbo-Croatian" in English, though this term is controversial for native speakers, and paraphrases such as "Bosnian-Croatian-Montenegrin-Serbian" are therefore sometimes used instead, especially in diplomatic circles.
In the late medieval period up to the 17th century, the majority of semi-autonomous Croatia was ruled by two domestic dynasties of princes (banovi), the Zrinski and the Frankopan, which were linked by inter-marriage. Toward the 17th century, both of them attempted to unify Croatia both culturally and linguistically, writing in a mixture of all three principal dialects (Chakavian, Kajkavian and Shtokavian), and calling it "Croatian", "Dalmatian", or "Slavonian". It is still used now in parts of Istria, which became a crossroads of various mixtures of Chakavian with Ekavian/Ijekavian/Ikavian dialects.
The most standardized form (Kajkavian–Ikavian) became the cultivated language of administration and intellectuals from the Istrian peninsula along the Croatian coast, across central Croatia up into the northern valleys of the Drava and the Mura. The cultural apex of this 17th century idiom is represented by the editions of "Adrianskoga mora sirena" ("Siren of Adriatic Sea") by Petar Zrinski and "Putni tovaruš" ("Traveling escort") by Katarina Zrinska.
However, this first linguistic renaissance in Croatia was halted by the political execution of Petar Zrinski and Fran Krsto Frankopan by the Holy Roman Emperor Leopold I in Vienna in 1671. Subsequently the Croatian elite in the 18th century gradually abandoned this combined Croatian standard.