The border of the new Czechoslovakia was drawn down the middle of the Danube, and that cut the town in two: the north bank became Komárno in Czechoslovakia, the south bank Komárom in Hungary. In the spring of 1919 Hungarian troops tried to force a crossing here and take the north bank back; they were thrown back with heavy losses. The Treaty of Trianon, signed on 4 June 1920, made the division permanent. One town, one parish, one fortress system and a great many families were now split by a river that had always joined them.Hranicu nového Československa viedli stredom Dunaja, čím sa mesto rozdelilo na dve časti: severný breh sa stal československým Komárnom, južný maďarským Komáromom. Na jar 1919 sa maďarské vojská pokúsili prejsť cez rieku a severný breh získať späť; s ťažkými stratami ich odrazili. Trianonská zmluva podpísaná 4. júna 1920 rozdelenie potvrdila natrvalo. Jedno mesto, jedna farnosť, jeden pevnostný systém a množstvo rodín boli odrazu rozdelené riekou, ktorá ich dovtedy vždy spájala.
