Svatopluk, however, entered the so-called Wilhelminer War on the side of Aribo and the emperor.

Svatopluk, however, soon assembled a large army and attacked the Bavarians who had been left behind under the command of Bishop Emriacho of Regensburg to guard ships on the bank of the river Danube.

Arbo, however, appealed for and received help from both Charles the Fat and Svatopluk, and even handed his son over to the latter as a hostage.

Arnulf, however, refused to hand over them, to which Svatopluk responded with further invasions.

Peace between Arnulf and Svatopluk, however, was only sealed in the latter part of the following year.

A quarrel broke out in Poland over the succession, with Bořivoj and his cousin Svatopluk supporting Zbigniew against the legitimate heir Boleslaus III of Poland.

Svatopluk established good relationship with the popes, thus he and his people were taken under the protection of the Holy See in 880.

Carloman's governors, William and Engelschalk were also both slain, thus Svatopluk became the undisputed ruler of Moravia.

Nevertheless, in 1722 Michael Bencsik, a professor of Hungarian law at the University of Trnava, suggested that the nobility and the whole population of Trenčín county within the Kingdom of Hungary were " the remnants of Svatopluk who sold his country to the Hungarians, and thus the Slovak people, into eternal serfdom ".

Arnulf did not make peace with Svatopluk until late 885, by which time the Moravian was a man of the emperor.

In 893, a new pope, Formosus, not trusting the newly crowned co-emperors Guy and Lambert, sent an embassy to Omuntesberch, where Arnulf was holding a Diet with Svatopluk, to request Arnulf come and liberate Italy, where he would be crowned in Rome.

At the time of Svatopluk I and King Arnulf of Carinthia in the 9th century, Silesia was a part of Greater Moravia ; after its destruction in the early 10th century, it was conquered by Bohemia.

In Slovakia, the cross of Lorraine as a symbol of Lorraine is considered to have arisen when the Great Moravian king Svatopluk I " passed " it to Zwentibold of Lorraine, the godchild of Svatopluk and son of the emperor Arnulf of Carinthia.

At that moment, Arnulf, king of Carinthia, at war with the Slav ruler Svatopluk, king of Great Moravia, decided like the Byzantines to appeal to the Hungarians.

Before 862, the seven Magyar tribes, living in the area they called Etelköz, seceded from the Khazars ; afterwards, they were exacting tribute from the neighbouring Slavic tribes and they fought occasionally as mercenaries on behalf of King Carloman of Bavaria, King Arnulf I of Germany and King Svatopluk I of Great Moravia.

Learning of this, Svatopluk sent ambassadors to Arnulf, demanding that the sons of Wilhelm and Engelschalk be immediately sent away.

They seems to have been hired either by Svatopluk or by Arnulf in order to intervene in their conflict.

At the meeting Svatopluk transmitted to Arnulf a message from Pope Stephen V, urging the king to invade Italy to protect the Holy See.

According to Regino of Prüm, the two monarchs also concluded an agreement, in which Arnulf ceded the ducatus of the Bohemians to Svatopluk.

Although, at least according to the testimony of the Byzantine Emperor Constantine Porphyrogenitus, Svatopluk had made a deathbed request to his sons that they remain united, after his death internal disagreements between his sons, Mojmír II and Svatopluk II were fostered by Arnulf.

He seems to have no idea about the real state of affairs in the Carpathian Basin at the time of the Magyar Conquest: instead of Simeon I of Bulgaria, Arnulf and Svatopluk, of whom he had no knowledge, he invented imaginary figures as enemies of the Hungarians.

Probably around 874 they were subjugated by the Great Moravian king Svatopluk I, who was a contemporary of the emperor Arnulf, and the Vistulan duke was forced to accept baptism.

By means of Zwentibold ( the ruler of Lorraine, son of the German emperor Arnulf of Carinthia and godchild of the Great Moravian king Svatopluk I ), this symbol got to Lorraine and is called the cross of Lorraine there.

In 869 Pope Hadrian II who had decided to revive the archdiocese of Illyricum consecrated Methodius archbishop of Sirmium ( Sremska Mitrovica, Serbia ) and papal legate of all the Slavs living in the territories ruled by Rastislav, Svatopluk and Pribina's son, Koceľ.

Svatopluk also promised never to invade Charles the Fat's realm with a hostile force as long as he lived, while Charles the Fat recognized him as a prince of his realm.

This ruined Arnulf's relationship with his uncle the Emperor and put him at war with Svatopluk of Moravia.

Methodius now continued the work among the Slavs alone ; not at first in Great Moravia, but in Pannonia ( in the Balaton Principality ), owing to the political circumstances of the former country, where Rastislav had been taken captive by his nephew Svatopluk, then delivered over to Carloman, and condemned in a diet of the empire at the end of 870.

His authority was restricted in Pannonia when after Koceľ's death the principality was administered by German nobles ; but Svatopluk now ruled with practical independence in Great Moravia, and expelled the German clergy.

* Svatopluk I becomes king of Great Moravia.

* The territory of the Vistulans is conquered by King Svatopluk I of Great Moravia.

On the other hand, such a compound structure name was already known from Great Moravia, as in the rulers named Svatopluk.

* Mojmír II becomes King of Great Moravia after the death of his father Svatopluk I.

* Prince Svatopluk I of Great Moravia occupies the territory of the Lusatian Serbs.

* The Balaton Principality is conquered by King Svatopluk I of Great Moravia.

Great Moravia during the reign of Svatopluk I

Ladislaus was preparing a campaign against Duke Břetislav II of Bohemia in order to help his sister's sons, Dukes Svatopluk and Otto II of Moravia, when he was informed that Coloman had come back to Hungary in the company of Polish troops.

Svatopluk I, ruler of Great Moravia, took up Aribo's cause and, in 884 at Kaumberg, took an oath of fidelity to Charles.

In the beginning of 1099, Coloman allied himself with his cousins, Duke Svatopluk of Moravia and Duke Otto II of Olomouc against Duke Břetislav II of Bohemia, but he had a meeting, on 29 May, with Břetislav II on the so-called Lucko Field ( near present Uherský Brod ) where they made a peace.

In 1107, Coloman and Bolesław III gave assistance to Duke Svatopluk of Moravia against Duke Borivoj II of Bohemia.

Map of Great Moravia at its possible greatest territorial extent during the reign of Svatopluk I ( 871 – 894 ), superimposed on the modern borders of European states.

Bořivoj was recognised as such around 872 by his overlord Svatopluk I of Great Moravia, who dispatched Bishop Methodius to begin the conversion of the Bohemian Slavs to Christianity.

He was restored in 885 only with the support of his suzerain Svatopluk of Moravia.

He was still a minor upon his father's death c. 889, and the Bohemian lands were placed under the regency of their suzerain Prince Svatopluk I of Great Moravia.

Zwentibold was named after his godfather, King Svatopluk I of Great Moravia ( Zwentibold being a Frankish transcription of Svatopluk ).

During the reign of Svatopluk I northwestern Hungary was conquered by Great Moravia.

Aribo maintained peace with Svatopluk of Moravia and it paid off when, in 882, the son of the late margrave Engelschalk, Engelschalk II, rebelled against him, claiming the rights to the march.