Esztergom ( ; ; or ; , known by alternative names) is a city with county rights in northern Hungary, northwest of the capital Budapest. It lies in Komárom-Esztergom County, on the right bank of the river Danube, which forms the border with Slovakia there. Esztergom was the capital of Hungary from the 10th until the mid-13th century when King Béla IV of Hungary moved the royal seat to Buda. Esztergom is the seat of the prímás (see Primate) of the Roman Catholic Church in Hungary, and the former seat of the Constitutional Court of Hungary. The city has a Christian Museum with the largest ecclesiastical collection in Hungary. Its cathedral, Esztergom Basilica, is the largest church in Hungary. Toponym The Roman town was called Solva. The medieval Latin name was Strigonium. The first early medieval mention is "ſtrigonensis [strigonensis] comes" (1079-1080). The first interpretation of the name was suggested by Antonio Bonfini. He tried to explain it from Istrogranum, "city at the confluence of Ister (the Greek name of the Danube river) and Gran (the Latin name of the river Hron)". This interpretation is still popular. Viktor Récsey attempted to derive the name from Germanic languages. After the conquest of the country by Charlemagne, the Franks should give the name Osterringun to their easternmost castle; as a comparison, a reference is made to the town of Östringen. Pavel Jozef Šafárik tried to explain the name from Slavic ostřehu (). Gyula Pauler suggested a Slavic personal name Stigran without a deeper analysis of its origin. In 1927, Konrad Schünemann summarized these older views and proposed the origin in a Slavic stem strěg ("custodia", guard). This theory was later extended by Ján Stanislav who also explained the origin of the initial vowel missing in Latin and later Czech sources (Střehom). The introduction of a vowel before the initial consonant group is a regular change in the Hungarian language (Stephan → István, strecha → esztercha), but the initial "O" in later Slavic forms can be explained by an independent change–an incorrect decomposition of the Slavic prepositional form. Both authors noticed the high number of Slavic placenames in the region (Vyšegrad, Pleš, Kokot, Drug, Komárno, Toplica, etc.) and similar Slavic names in other countries (Strzegom, Střehom, Stregowa, etc.). Both authors believed that the stem strěg was a part of the Slavic personal name, but Šimon Ondruš suggests a straightforward etymology. The Proto-Slavic –