Dominic Mandić, Journal of Croatian Studies, I, 1960, pages 32-43
Three powerful states flourished in Southeastern Europe at the beginning of the tenth century: Byzantine Empire, Bulgaria, and Croatia. Croatia spread from the Raga River in Istria to the Drin in today's Albania, and from the Adriatic Sea to the Drava and Danube Rivers in the north, and to the Drina River in the east. The country was divided into White Croatia, from the Raga to the Cetina in Dalmatia, and Red Croatia, from the Cetina to the Drin. Bulgaria extended over the territory from the Morava River to the Black Sea, and from the Danube to Adrianople and Salonika. It spanned over what is today Bulgaria, Macedonia, a greater part of Serbia, Albania, except a small coastal strip, and a large part of northern continental Greece. Serbia was then a small country between the central Drina and the Morava. It was called Rascia. Since its origin in the seventh, century, Serbia was either subjected to the Byzantine Empire or dependent on Croatia. In the beginning of the tenth century, it became a dependent at one time of the Byzantine Empire, at another time either of Bulgaria or Croatia.
In the second decade of the tenth century, Croatia and Bulgaria were, at the zenith of their powers. Tomislav, the first Croatian king (c. 910-929), ruled Croatia; Symeon the Great (893-927), duke and later emperor, ruled Bulgaria. During Tomislav's reign, Croatia had an army of 100,000 infantrymen and 60,000 mounted soldiers. Its navy consisted of 80 large and 100 small ships. Tomislav was conscious of his power. He courageously repelled neighboring enemies, particularly Magyars, whom he defeated several times. However, he neither attacked neighbors nor longed for their territories. The Bulgarian ruler, Symeon, was a wise and able man with a restless and insatiable spirit. He spent his entire life fighting battles with neighboring countries. His basic aim was to defeat the Byzantine Empire and conquer Byzantium so that he could rule the Balkans as the "Emperor of the .Bulgarians and Greeks". To achieve his aim, Symeon overran the eastern and central Balkans several times, occupied Serbia and finally attacked Croatia. Constantine Porphyrogenitus recorded the event in his work De administrando Imperio, written between 948 and 952. After describing how the Serbian great župan Zacharias fled to Croatia, when Symeon attacked him for the second time, Porphyrogenitus continues, "Now, at that time these same Bulgarians under Alogobotour entered Croatia to make war, and there they were all slain by the Croats."
Porphyrogenitus did not state the year when that occurred. However, some historians, among them Croatian historians Rački, Klaić, and others, concluded on the basis of Porphyrogenitus' data about Serbian history that the event had to occur in 925. Zlatarski, the greatest Bulgarian historian, holds the same opinion. Croatian historian Šišić. English historian Runciman, Ostrogorsky and others date the event with 926 A.D. on the basis of the same data. It should be observed that the exact time when the Bulgarians attacked the Croats could not be established on the basis of Serbian history. After the description of Symeon's war against Serbia, Porphyrogenitus starts the description of the war with the Croats with the words “κατά τòν καιρòν οΰν…” which do not really mean, "now at that time," or "then, immediately after that," but rather, "at opportune, favorable time". Such an expression allows a possibility that the Bulgarian attack on Croatia did not immediately follow the second attack on Zacharias, but rather that some time elapsed between them. Our explanation is particularly true for Porphyrogenitus who, in his works, uses the expression "now" (νΰν) and "just now" (άρτι) for the period of ten and one hundred years.
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