The cemetery from the Roman Period at Modła, comm. Wiśniewo, distr. Mława, was excavated in total in the years 1976–1986. More than 300 ancient features were discovered, which were almost exclusively graves from the end of the old and the first ages of the new era: over 190 graves from the Przeworsk Culture (from the final stage of phase A3 to the late stage of phase B2), around 60 graves from the Wielbark Culture (from phase B2/C1 to the early phase of the Migration Period), and around 45 further graves of undetermined cultural origin, surely, or most probably from the Roman Period. The majority of the graves from Modła contained cremation burials. Relatively few of them were inhumation graves – there were only 23 such graves discovered. During the anthropological studies of the bone remains from one of the inhumation graves (no. 169) it was noted that the buried individual had been subjected to an intravital skull trepanation. This discovery deserves special attention as it is probably the first recorded case of such an operation from the Roman Period at the territory of Poland. Grave 169 was situated at the south-astern border of the cemetery, at a distinct slope of a hill at which the cemetery was located – about 5 meters below the top of the hill. The bones of the skeleton, oriented along the N-S axis, with the head to the north, were uncovered just under the surface, at the border of a large modern ditch. The description in the field log allows for a supposition that the burial was discovered in its original alignment. It is unknown, however, whether the unnatural arrangement of the skeleton was original or secondary (Fig. 1). The absence of any preserved furniture does not allow for precise dating of the burial, however, there is some indirect evidence indicating its cultural attributes. The orientation of the pit of grave 169 and the arrangement of the individual with the head to the north are typical of inhumation rituals of the Wielbark Culture. Among 23 inhumation graves from Modła, 18 most certainly or probably should be connected with the Wielbark Culture on the basis of the furniture, and only one should be connected with the Przeworsk Culture. Almost all pits of the inhumation graves were aligned N-S or NNW-SSE, and more seldom NW-SE or NE-SW. The only exception is the Early Roman Period grave from the Przeworsk Culture, with the pit oriented along the NWW-SEE axis and the skeleton oriented with the head to the west. At the north-western Mazowsze, in the zone occupied by the Wielbark Culture from the beginning of phase B2/C1, a series of about 20 inhumation graves from the Wielbark Culture at Modła is quite exceptional. Five inhumation graves are known from the cemetery at Litwinki, distr. Nidzica, at which no fewer than 50 graves were discovered, while at other cemeteries, only single such graves are recorded. This also concerns the big cemetery at Niedanowo, distr. Nidzica, site 2, where there was only one inhumation grave among over 200 hundred burials from the Wielbark Culture. In the case of the Przeworsk Culture at the entire territory of Mazowsze on the right side of the Vistula, inhumation graves are very rare (fewer than 15 graves in total). However, almost all of the them come from the northern limits of the Przeworsk settlement zone (Szczepkowo-Zalesie, Bartki, and Niedanowo, distr. Nidzica, Modła, distr. Mława, Zgliczyn-Pobodzy, distr. Żuromin). The grave pits are variously aligned, although the orientation W-E and similar ones dominate, and the bodies of the dead were often laid on the side, and (or) with the legs pulled up. This absence of clear rules concerning the orientation of the grave and the arrangement of the body is characteristic of the inhumation ritual also at other areas of the Przeworsk Culture. The evidence presented above allows us to connect grave 169 with the Wielbark Culture and to date it generally to the Late Roman Period. The bones from grave 169 belonged to one individual. The gender features were not clear. However, the relatively big size and massiveness of individual bones (eg ribs, vertebrae, mastoid processes), the angle value between the neck and the shaft of proximal femur (ca 125°), and also the shape of the upper rim of the orbit and occipital, point to a male. The determination of the age of the dead was not easy because of the discrepancy between the ectocranial suture closure and dental age. All preserved fragments of the cranial sutures were exo- and endocranially opened on both sides. On the other hand, the degree of attrition of the surfaces of the masticatory system was quite considerable. It may be assumed that the skeleton under study belonged to a male individual who died at the age of early adultus (ca 20–25 years). He was around 165.5 cm tall. At two parietal bones, in the area beginning in the middle of the sagittal suture (pars lambdoidea, and pars obelica) and ending at the joint with the occipital bone (the area of lambda point), there is an oval hole (Fig. 2). The size of the cavity in the sagittal plane measured ca 59 mm, while in the frontal plane it was 39.5 mm. At the same time, the edges of this cavity were damaged post mortem in the area of lambda point and it was on the opposite site of the cavity. The actual post-trepanation hole was slightly smaller (48.5×39.5 mm). The characteristics of this cavity allows us to view it beyond any doubt as a hole resulting from craniotomy (status post trepanationem). The operation was carried out in vivo, which is supported by the fact that the edges of the cavity had healed intravitally (cf Figs. 2 and 3). An analysis of the bone margin at the outline of the hole (11.9 mm) points to a relatively long intravital period, which indirectly suggests that the trepanation could have taken place at a young age. The post-trepanation hole was made by using the method of scraping which was the most common method in all ancient periods. This is why the cavity had a regular oval shape, with the wall gently inclined inside, which is described in the literature as completed trepanation (involving the perforation of lamina interna). The location of the cavity is worth noting. It is in the parietal bones, close to the sagittal suture and the lambda point, as the middle zone of the head is connected with greater risk in such operations. This is due to the fact that right under the lid of the skull there is the Sinus sagittalis, whose disruption can result in instant death either due to vein damage or due to infection. The described surgical intervention belonged to the so called healing trepanations. However, a ritual (magical) character of this operation cannot be excluded. Everything points to the fact that the reasons for the craniotomy in the case of the individual in Modła were connected with the morphological features of his skull. The skull was characterized by an asymmetry (particular visible in the area of frontal, occipital and both temporal bones), the occipital scale was indented and had an irregular line of the nuchal crest and of the protuberantia occipitalis externa. This may testify to a pathological state of traumatic origin (injury of the occipital skull part). The bone density, visible in the X-ray picture agrees with age group of the individual obtained by anthropological methods. No signs of developmental disorders were observed in the bone structure (Fig. 3). Also the histological picture of bone trabecular tissue is symmetrical and regular, and no pathological changes are observed (Fig. 6). As far as the medical consequences of damaging the occipital lobe go (Brodman’s area 17 – V1 and V3), it can be assumed that the young man, following the craniotomy, could suffer from vision disorder. Only few cases of craniotomy are known from the area of Central Europe from the period between the late Neolithic and the early Middle Ages, which can be due to the insufficient state of research, small popularity of this operation type, but also the domination of cremation rite. Relatively numerous healing trepanations are recorded in Celtic materials from the present day area of Southern Germany, Austria, Bohemia, Moravia and Slovakia. The only case of skull trepanation in vivo known from the territory of Poland and chronologically close to the find from Modła was recorded recently in grave 68 at an Oksywie Culture cemetery at Różyny, distr. Pruszcz Gdański (pow. gdański) – a burial of a male individual, age: senilis, and dated to phase A2 of the Late Pre-Roman Period. Three cases of craniotomy contemporaneous with the burial at Modła (coming from phases B2/C1–C2) were recorded at a big necropolis in Marvelė, ray. Kaunas in Lithuania. Apparently also from the Late Roman Period came the burial from the town of Nitranský Hrádok, distr. Nové Zámky, in Slovakia, while the grave from Merseburg-Süd, distr. Merseburg-Querfurt, in Sachsen-Anhalt is dated to the second half of the 4th cent. and the beginning of the 5th cent. AD. This chronological sequence, the territorial dispersion of graves with burials containing individuals with trepanation and the established fact that the operated individuals survived the trepanation indicates to us that the exceptionality of these cases is only apparent, and the surgical procedures connected with this type of operation had to be well known to the ‘barbarian’ medics of the time. This view is corroborated indirectly also by the surgical sets with instruments used for trepanation, which come from the Central and Southern European zone of Celtic settlement. A similar set (but without bone saws) is known from a warrior grave from a cemetery of the Przeworsk Culture at Żukowice, distr. Głogów, in Lower Silesia, dated to phase A1. Recently, Anette Frölich identified small trepanation saws, identical to the Celtic ones, in three coherent sets of personal grave furniture from the known bog deposit from Illerup in northern Jutland, to which also belonged scalpels and wooden needles for ‘rough sewing’ of cut wounds. It would therefore seem that we are dealing with some sort of first aid sets, most handy at battle fields and used by the ‘military’ medics of the time. Ernst Künzl describes the Celts buried with weapons and sets of medical instruments as warrior-surgeons – most surely the warrior from Żukowice was a ‘surgeon’ of this type. Head wounds, expected in battle conditions and the necessity of quick surgical interventions support the earlier expressed opinion, according to which craniotomy at the time of late antiquity at the territory of Central and Northern Europe were mostly healing in character. The sets from Illerup force us to assume that not only the necessity of such operations was taken into account, but also the necessary instruments and skills for their effective use in battle conditions.