FOUR LAKES FROM A MERCATOR ' S MAP OF CROATIAN REGIONS AND CAUSES OF THEIR EXTINCTION

The author proves the existence of four lakes on a Mercator's map from AD 1593. In the first part he explains the genesis of the map. The causes why the lakes disappeared and when it happened were adduced in the second part of the paper.

The map was drawn by famous cartographer Gerhard Kremer (1512-1594), who was born in Flander.He himself latinized his own name in accordance with then ruling views and fashion, so that he is much more known as Gerardus Mercator.The greater part of his works was created in Duisburg, in Germany (BROWN, 1950), therefore all of possible errors should be excusable and understandable.It is a matter of fact, that he had never been in Croatia.For this reason it remained as a far strange country for him, and with its geographical facts he was acquainted intermediately -by the works of other cartographers.
Question arises, who were primary map-drawers of those regions?Knowing the Mediterranean cartographer circle, there is no doubt, that one among them was Martin Kolunić-Rota (1532-1583)1 , Croat from the city of Šibenik.He was an engraver retained by the Vienna court, whose maps were used by much more known Venetian Francesco Camocio, the author of the famous portolano "Isole famose" from AD 1573 (MARKOVIĆ, 1993;SLUKAN, 1998).So, in the Kolunić's2 survey of the Šibenik district from the time of the Cyprus War (1570-1573) (HDAZg, D.XIV.40.), a detailed depiction is noticeable in the nearest surroundings of Šibenik and other coast places as well, but this minuteness falls off towards the upper map margin.In some measure it repeats the story equal to the Mercator's one.In other words, it is hard to believe, that Kolunić himself had an opportunity to reconnoitre farther hinterland and to note toponym locations within Ottoman frontier.It is well known that Ottoman government never allowed anybody to gather geographical informations, because it was considered to be an espionage, menacing with the penalty of impalement.For that reason, the geo data from the territory under Ottoman control (Klis sanjak, Krka sanjak) were obtained from Ottoman citizens who came running some business in Šibenik, or, what was possible too, from the citizens of Šibenik, who were going, as merchants or emissaries, to the regions ruled by Osmanlis.To corroborate this thesis there is an example from 1574, when a Šibenik deputation went to Bosnia applying for admittance to the pasha.On that occasion they gathered plenty of information about territory that was travelled through (RAČKI, 1882).
So, taking over the data either from Kolunić's map directly, or from Camocio's one (what is out of relevance), Mercator inherited all exactnesses and unexactnesses.Now, studying above-mentioned Mercator's map of Croatian regions, it could be found a row of details which don't correspond with present situation, i. e. with the river, mountain and lake positions in this area.However, it is noticeable that the images of the Zrmanja, the Krka and the Cetina rivers are the closest to reality, indicating too that the author of Mercator's specimen was a person from that region -Martin Kolunić-Rota.

Lakes
Among all unaccordances with the present situation, four lakes in the basins of the river Krka and the river Cetina are deserving the greatest attention.With regard to neighbouring toponyms and to their places within two river basins it is easy to determine their position.Viewing from the northwest to the southeast the first lake is situated below the fortress and the town of Knin.The second lake is located in the spring part of the river Cetina, the third one lies below the fortress and the town of Sinj, while the fourth one is separated and has no visible water connection with any river.Nevertheless, it is manifest that it belongs to the river Cetina basin.Further, it was drawn as if it was situated near by the left bank of the river Cetina, on the southwest foot of mountain Dinara.
In the case of the first lake, toponyms on the map speak incontrovertibly on behalf of Knin.Tina is a fortress and the town of Knin, Capitulo is hillock Kapitul, Hoton is the village Oton, Stermichi is the village Strmica, and Butisin fl. is the river Butišnica.Considering geological and hydrographical characteristics of Knin surroundings, it is obvious that the town is situated in a depression overtopped by the Dinara massif (1831 m) from the east side (FRIGANOVIĆ, 1961).The main water stream is the river Krka, which springs on the east side of the depression.Having received three smaller tributaries, it flows out through the deep cut gorge in the southwest direction (FRIGANOVIĆ, 1961).The bottom of the depression -better said -the karst polje of Knin, consists of Permian-Triassic gypsum layers and lower Triassic slates overlayed with Neogenic clay and Pleistocene alluvium (FRIGANOVIĆ, 1961).It could be seen, after all, that prerequisite conditions to a lake existence were propitious.Typologically considered, the lake was a tectono-karstic one (HUTCHINSON, 1957;NEJAŠMIĆ, 1998).Let's call it further as "Lake of Knin", for the sake of distinction.
Judging by the Mercator's map, the three others were situated in the upper stream basin of the Cetina river.Its source is on the north edge of the Cetina polje, afterwards it flows through poljes of Koljani, Ribarić, Hrvace and Sinj polje, as well.On the edge of the last one it enters the gorge cut in the calcareous stones.River Cetina receives one greater tributary from the left side and one smaller affluent from the right.Besides, there is a row of immediate sources down the left river bank (MAGDALENIĆ, 1971).From the northeast the whole area is dominated by mountains Dinara (1913 m) and Kamešnica (1856 m), while mountain Svilaja (1508 m) stretches on the southwest side.The substratum of the poljes was formed by the Neogenic clayish-marly sediments, what was favourable to the establishing of lake basins (MAGDALENIĆ, 1971).It is undoubted, that the second lake was situated in Cetina polje.It was a spring tectono-karstic lake (HUTCHINSON, 1957;NEJAŠMIĆ, 1998).We shall call it "Lake of Cetina".
The third one laid below the fortress and the town of Sinj (on the map it is written: Sfinga), indeed, not to the northeast side -as it was drawn by Mercator -but to the east of the town.There is another mistake -the stream, which flows through the lake, is not a tributary of the Cetina, but the river Cetina itself.Consequently, the lake was situated in the broadest part of Sinj polje, between Sinj and the Kamešnica mountain slopes, and was classed as the combined tectono-karstic and flood plain lake (HUTCHINSON, 1957).This one will be called "Lake of Sinj".
In order to locate the fourth lake, the surrounding toponyms in the Mercator's map have been used.Clina is on the right bank of the Cetina river, to the northwest of the lake.To the west and south of the lake we see Cescouo traietto and Malcouo traietto.Finally, Morchi lies on the east bank of the lake.Thus, Clina is the present village Koljane, Malcouo traietto is a ford beside the village Maljkovo.It is obvious, that Cescouo traietto is another ford in the river Cetina too, but now it does not exist under this name.Fortunately, "Košnice" ford was mentioned in an Ottoman cadastre-book and it was situated near the then and now village Bitelić (SPAHO, 1985).Aforesaid Morchi, from the entire map context, could be identified as "Margude" from the cadastre-book (SPAHO, 1985), that is Mrgude meadows near the village Čitluk (FORTIS, 1984).Since Morchi, i. e. Mrgude is on the right side of the river Cetina, it is evident that the cartographer made a mistake having drawn the lake on the left, instead on the right side -to the southeast of the mentioned river fords.Just like the previous lakes, this one was a tectono-karstic lake, too (HUTCHINSON, 1957).Let's name it as "Lake of Krinj".
There are not any of these lakes in this area today, so a logical question strikes us -what happened to them?.

Little Ice Age
The Little Ice Age, the term introduced seventy years ago, was a period of worldwide lower temperatures lasting from about AD 1500 to about AD 1850 (GROVE, 1988).In Europe consequences depended not only upon a geographical latitude, but upon a height above sea-level (GROVE, 1988).As a main getting effect of cold, this period was characterized by increased precipitation amount -snowfall and rainfall.
It is a matter of fact that historical sources in Adriatic cities, analogous to the North European ones, are quite sufficient to illustrate diluvial rains and biting snows in the surroundings.Well, Venetian Marino Sanudo takes note of the cold in January 1517, and pouring rains in February 1518 in Venice and its surroundings (SANUDO, 1865).A chronicler from Udine bears witness of the climate, too.He mentions severe cold: during January and February 1541 (Diarii udinesi, 1884), and continual rain: from June till August 1538 and 1540 as well (Diarii udinesi, 1884).
For Croatian regions, too, annalists left us many notes about weather anomalies during the Little Ice Age, so that we can get a clear image of the change proportions3 .To mention some of them, let's begin with Sanudo's note of a downpour during October and November 1500, just in the Knin area (SANUDO, 1859).Among snowy tempests those ones from January and February 1549 (KUKULJEVIĆ SAKCINSKI, 1857), March 1550, the period from January till April 1551, March 1556, April 1559 were especially memorized (KUKULJEVIĆ SAKCINSKI, 1857).Besides this snow the torrential rain were noted on March (Annales …, 1883), June and August 1549, August and September 1551 again (KUKULJEVIĆ SAKCINSKI, 1857).For instance, present-day brackish Vrana lake (between Zadar and Šibenik) was mentioned as a fresh-water one in 1630.It could be an effect of the fall quantity (FORTIS, 1984).Further, above-mentioned deputation of Šibenik registered the existence of another lake, which disappeared subsequently, too (RAČKI, 1882).Moreover, the precipitation of such a large quantity used to create temporary lakes in the areas without surface streams (FORTIS, 1984).This is an excerpt from the notes of the Little Ice Age meteorological phenomena only.Although it is impossible to make an exact comparison with the precipitation in that time, let's see the present annual averages of Knin and Sinj.For the period 1961-1990 we know Knin had an average precipitation amount of 1074 mm water column as well as 5,1 snowing days.In Sinj it was registered 1206 mm and 6,6 days (ŠEGOTA, FILIPČIĆ, 1996).
The following effect of the Little Ice Age precipitation was an intensified erosion which resulted in filling up the lakes in the end.As it is known, the Little Ice Age lasted till the middle of the 19 th century, and there have been searching after information how long the lakes existed.Indeed, precipitation bears half a responsibility for eroding.For the other half the man is to be blamed.Many documents since 16 th century testify undeniably about his share in the erosion effect intensification.Just in that time Ottoman Empire had reached culmination in its conquests.Fortresses Knin and Sinj withstood them for about sixty years, and it was more than enough for Osmanlis to apply their usual methods of breaking resistance in the fortresses' surroundings.Economic basis was sistematically destroyed by culture plants ravage (ČELEBĪ, 1979) and forests' burning as well (MCNEILL, 1992).The military and political motives were substituted by economic reasons, originated from an extensive cattle-breeding during Venetian rule in the 18 th century.In order to enlarge pasture-grounds, the new-settled population was used to setting fire to forest remains (FORTIS, 1984;FRIGANOVIĆ, 1971).Taking it together, all of prerequisite conditions for erosion process were fulfilled.

Lake of Knin
According to the report of Venetian provvedditore Marino Michieli from AD 1685, it is known, that the lake below the fortress of Knin was still existing in this time.It extended eastward, and the river Krka was flowing through it.Besides this greater lake, there were several smaller lakes in the area of 5 miles long and 3 miles broad (DESNICA, 1951).Less than a hundred years later, scholar Alberto Fortis made a note of the swampy lake near Knin (FORTIS, 1984).In the fifth decade of the 19 th century, when English writer of travels A. A. Paton visited Knin, he did not mention the lake (PATON, 1849).Finally, there is information that already in AD 1856 the lake depth of 40 feet (FRIGANOVIĆ, 1961) was beared in mind.
It is evident that the lake covered the distance from maturity to extinction of two hundread and fifity years.The structure of infilling sediments, besides the forest soil, was formed mostly of travertine barriers stuff from the bed of brook Krčić.As early as Fortis observed that Krčić brook was carrying huge amounts of travertine stuff (FORTIS, 1984).To the present time only slight traces of great barriers have been left.To illustrate, one travertine fence was 300 m long and 15 m high (FRIGANOVIĆ, 1961).Likewise, in another tributary of the Krka near Knin -the river Butišnica, Fortis noticed a large mass of alluvium produced by the erosive work of spates (FORTIS, 1984).All that material from the Krčić bed was finally deposited into the river Krka, which infilled the lake with it.The recent researches have certified these Fortis' notes (FRIGANOVIĆ, 1961).Moreover, Fortis was the first who had pointed at urgent need for lowering of the travertine barriers in the river Krka bed, in order to make the lake drainage easier (FORTIS, 1984).Not long after it, it was actuated.At the end of the 18 th century a systematic drainage of the marsh, relict of the lake of Knin, began.The work was continued by the French and was mostly finished during the Austrian rule.At long last the barriers downstream of Knin were blasted -in order to quicken the water flow off.In such a way, encroaching on the nature directly, the man dealt coup de grâce to the lake (FRIGANOVIĆ, 1961).

Lake of Cetina
The oldest information about the first lake in the row of three one on the river Cetina is quite late.The lake next to the sources of the river was an intermittent one in the second half of the 18 th century.In summer-time, that is rainless period, only small marshes and backwaters would remain (FORTIS, 1984).

Lake of Sinj
A valuable note about this lake is to be found in the Ottoman cadastre-book of the Sinj district from 1604.In the document it was mentioned as Veliko jezero (i.e. English -Great Lake) (SPAHO, 1985).During fights around Sinj in AD 1687 an overflow, i. e. lake periodicity was mentioned (DESNICA, 1951).A hundred and sixty years afterwards, Wilkinson travelled through the Sinj countryside, while abovesaid Paton visited it shortly after him.It occurred opportunely, Wilkinson was there during dry period, while Paton' s stay occurred in rainy season.When we compare their textes the periodicity of Sinj's lake is more than evident.Wilkinson does not mention the lake at all, but catches sight of … small torrent bed, dry in summer and boasting very little water in winter… (WILKINSON, 1848).To the contrary, Paton emphasises that he … saw a blue lake, of oval shape, filling up a considerable part of the valley below me, formed by the river, which here spread out so as to form a lake …, soon after, … Sign … was at the upper part of the lake …, and once again, … the ground on which Sign is built rises gradually from the edge of the lake formed by the Cetigne …(PATON, 1848) (Cetigne is the river Cetina.) When the southwest slope of Dinara mountain, because of human's regardlessness, was rapidly deforested, the precipitation of the Little Ice Age weared down the unprotected soil into the river Cetina.Due to such incidents, the lake of Cetina was first filled with sediments in the 18 th century, while the lake of Sinj came to its end recently. 4Namely, its swamp was drained early in 20 th century, when an amelioration of the river course was carried out.

Lake of Krinj
Finally, the first written record of this lake appears in the same Ottoman cadastre-book from AD 1604.It was mentioned there as Vesarlik (Turkish -vizier's property), while hundred and sixty years later in a travelogue an account of two small lakes of Krinj was given (SPAHO, 1985;FORTIS, 1984), which should be considered as an advanced stage of its extinction.However, this lake, truth to say, transformed into a twinbog (FORTIS, 1984), outlived the Little Ice Age.The explanation why it was not filled is easy to be understood.First, this lake has not been influenced by the river Cetina, and second, a brook which discharges into, has a smaller drainage basin, and proportionally a lesser alluvium quantity.Well, the only lake of four ones from AD 1593, exists as a relict -in fact, as a swamp.
As a curiosity concerning the subject matter, it has to be said that the man, having built a dam on the river Cetina, formed a new artificial lake in the fifties.

Map-drawers II
Before drawing a conclusion, let's look at a few maps of the same area, but from different periods.The first map, almost contemporary one is the Barents' "Tabvla Sinvs Venetici" from AD 1595.On this chart only one lake -our "lake of Sinj" appears.What could be cause of it?Since we know that Willem Barents (1550-1597) was a sea explorer, there is every reason to believe that he had no interest in interior waters.Yet, this chart was drawn for the purpose of sea navigation (KOZLIČIĆ, 1999).
It is surprising that a native scholar -historian and map-drawer Ivan Lučić (1604-1679) depicted only one lake, too -this time "lake of Knin".This map "Illyricvm hodiernvm" is a supplement of his masterwork "De Regno Dalmatiae et Croatiae" from AD 1668.While Barents was made to draw by commercial reasons, Lučić was inspired by political ones.He was dreaming of expulsion of Ottomans.Therefore the map was dedicated to count Petar Zrinski, famous war commander in Croatia (MARKOVIĆ, 1993; P. Kužić: Four Lakes from a Mercator's Map... Geoadria, vol. 6, 5 -15, 2001.12 KOZLIČIĆ, 1995).For this reason it would be expected of him to have entered with more minutiae geo facts.Most probably the cause lies in the cruel Candia War (1645-1669)with its restriction in gathering information.Knowing Lučić's scrupulous soundness, there is no wonder he did not dare to draw unseen things (KURELAC, 1969).
Lastly, Giacomo Cantelli da Vignola (1643-1695) made the map entitled "Dalmatia descritta" (HDAZg, A.II.23).He was among the most famous Italian cartographers from the late 17 th century.This doesn't prevent us from saying that his map is a mere baroque copy of Mercator's map -decorated and antiquated.At the first sight it is evident that all forms -rivers, mountains, even islands -were copied by Cantelli.Moreover, the incorrectly engraved toponyms are identical with the Mercator's ones.Consequently, although all the lakes have been represented, Cantelli's work cannot be considered as a real depiction and a reliable source of geo facts of his time.

Conclusion
The problem of the four lakes drawn in the Mercator's map of the Croatian regions from AD 1593 is fully solved.Their life history ended in the recent historical time.Factors that affected extinction were climatological phenomena of Little Ice Age and peculiarity of carstic geology as well.The third originator was the man, finally, he was a merciless executor of the lake relicts.He is also responsible for drainage of lakes, besides the natural infilling by sediments.It is hard to say what was more baleful -war ravaging or relentless cattle-breeding.Indeed, trustworthiness of chart makers of the sixteenth century is the most important thing that was substantiated by this work.It has been found that the cartography of that period, although suffering from inaccuracy, brought valuble information.Under existing conditions and, in consideration of information indirectness, every single map is a real miracle of the human achievement.The information tree whose anonymous emissary from Šibenik was the root, and Mercator's map was a leaf, has still yielding.