EN[...] In order to learn about the 'lost' 13th-14th century period in Lithuanian archaeology, one type of very abundant find group, the so-called penannular brooches, was selected as a large percentage of the finds have been chronologically identified in studying the late 14th-15th-century Christianisation of the GDL. In Lithuanian literature, the finds of this type are generally called 'horseshoe brooches with animal-shaped terminals'. [...] So-called penannular brooches with zoomorphic terminals have been found in very large numbers during excavations at not only Lithuanian but also Latvian archaeological sites. They are found in much smaller numbers in Estonian and former East Prussian (now Kaliningrad Oblast, Russian Federation) archaeological sites. These brooches are the least known from Belarusian, Danish, Polish, Russian, Finnish, continental Swedish, Sweden's Gotland Island, and German sites. The very abundant finds of such brooches in the territories of present-day Lithuania and Latvia allows one to hypothesise that they could have been manufactured in the lands of Lithuania's Christian neighbours, the Livonian Order and the Teutonic Knights, whose masters were guided by contemporaneous bestiaries. A bestiary (from the Latin bestiarium, the neuter of bestiarius 'belonging to animals' from bestia 'animal, beast') is an illustrated didactic book of animals symbols that contains descriptions illustrated by miniatures of the beasts. [...] In order to prove the hypothesis of the origin of so-called penannular brooches with zoomorphic terminals among Lithuania's Christian neighbours, the Livonian Order and the Teutonic Knights, it will be necessary to answer several essential questions, e.g. when and in which contemporaneous lands these artefacts were commonplace. In this case it is possible to say that it is difficult for any investigator of 13th century Lithuanian, Latvian, Estonian, and East Prussian history [...].[...] The so-called penannular brooches with zoomorphic terminals (OBZT) were described as 'omega brooches with unicorn and lily terminals'. OBZT have been found in various assemblages and by chance. This has resulted in classification into five groups: 1) cremations and suspected cremations with OBZT, 2) inhumations with OBZT, 3) hoards with OBZT, 4) sacrificial sites with OBZT, and 5) chance find OBZT. Images of all these brooches are presented in the second volume of this monograph. Over 1200 OBZT (499 in Lithuania, 567 in Latvia, 58 in East Prussia, 35 in Estonia, 20 in Belarus, 16 in Gotland, 6 in Finland, 4 in Germany, 3 in Poland, 3 in Russia, 1 in Denmark, and 1 in Ukraine) were collected for classification. After evaluating their condition, it was determined that there are 719 complete OBZT, i.e. with two terminals, the shank, and the pin, 28 with only one terminal, 277 with no pin, and 186 in fragmentary condition (one terminal or a terminal with part of the shank). Among the collected material, only a little over ten OBZT remained unclassified. The brooches were marked by especially great diversity. They are of various sizes: miniature, average, and large, the last weighing more than 400 grams. The OBZT were classified into six variants and individual brooches. Four OBZT variants were further classified into subvariants on the basis of the differently portrayed snout and ear elements: three subvariants in variant 1, two each in variants 2, 3, and 5. [...] OBZT chronology should be defined very broadly from the second half of the 11th to the first quarter of the 17th centuries. [...] After careful examination of the assemblages comprising the OBZT clusters, it is seen that residual artefacts which are from one to several centuries older, are found in them.After taking into consideration the factor of residual artefacts and the dating of the chronologically studied artefacts comprising the clusters, the chronology of variant 1 and 2 OBZT can be defined as the second half of the 13th-15th centuries, variant 3 the 14th-15th centuries, variant 4 the 14th - first half of the 15th century, variant 5 the second half of the 13th - first half of the 15th century, and variant 6 the 13th-16th centuries. The geopolitical incidence of OBZT during the 13th-15th centuries shows that variant 1-3 and variant 5-6 artefacts are mostly found in Livonia and in Curonian, Semigallian, Scalvian, and Samogitian lands, which stretched from the Baltic Sea to the River Nevėžis and did not belong to the Lithuanian state until the 1410s, but a large percentage of these lands were not incorporated into either the lands of the Teutonic Knights or Livonia. The geopolitical incidence of variant 4 OBZT during the 14th - first half of the 15th century shows that these artefacts are not found in the broad coastal strip near the Baltic Sea, i.e. in Curonian lands, while the absolute majority are found to the E, from central Samogitia to the upper reaches of the Nevėžis and the middle reaches of the Šventoji. [...] In summarising the classification, chronology, geopolitical incidence, and symbolic content of OBZT, it is possible to state that these artefacts appeared in the E lands of the Baltic Sea in the 13th-14th centuries during the Baltic crusade. OBZT were manufactured in accordance with the Christian bestiaries in the lands of Lithuania's Christian neighbours, the Livonian Order and the Teutonic Knights and were intended for the Christianisation of the inhabitants of colonised lands. But the purpose of these artefacts in confederated Livonia and the lands of the Teutonic Knights in the 13th-14th centuries was different than in the so-called pagan lands [...]. [From the publication]