The State of Cristus, originally known as the Kingdom of Cristus, was founded on 24 September 2023 by a group led by Connor Klinkosch.

Originally claiming a piece of territory on the right bank of the Danube river, which was claimed by both Serbia and Croatia, due to the mistaken belief that the territory was terra nullius, Cristarian authorities contacted the Gaplan authorities on 25 October 2023 to notify them of the competing territorial claim. When Gaplan authorities revealed that there was no territorial conflict and that the territory claimed by Cristus was not terra nullius, Gaplan authorities proposed a federation composed of two constituent states, with New Apatin forming the State of Cristus.

In a landmark agreement in Gaplan and Cristarian history, the Kingdom of Cristus joined the Federated States of Gapla as the State of Cristus on 29 October 2023, obtaining the formerly terra nullius pocket west of Apatin as its territory.