Baron Janez Vajkard Valvasor or Johann Weikhard Freiherr von Valvasor (or Valvasour), Freiherr zu Gallenegg und Neudorff, Herr zu Wagensperg und Liechtenberg (baptized on May 28, 1641 - September 19, 1693) was a Slovenian nobleman, a scholar and polymath, and a Fellow of The Royal Society, which gives "soldier" as his profession and "Austrian" as his nationality.
Neither the exact day nor the actual place of his birth are known, but from the fact that his baptism was registered at St. Nicholas Church in Ljubljana it appears very likely that he was also born in Ljubljana, Carniola (present-day Slovenia) in May 1641 as the twelfth child to father Jernej (German: Bartholomäus) and mother Ana Marija b. Ravbar (Anna Maria Freiin von Rauber), who did not only live at their family castle Medija/Gallenegg in Izlake but also had a town residence in Ljubljana at "Alter Markt", today No. 4 Stari trg. His godparents were Freiherr (Baron) Konrad Ruess von Ruessenstein from Strmol/Stermol and Regina Dorothea Rasp from Krumperk/Kreutberg.
Valvasor's father died when he was ten years old. At the time he was already attending the Jesuit school in Ljubljana. Graduating in 1658 at the age of seventeen, he did not choose to continue his studies at a university but decided to broaden his horizons by meeting learned men on a journey across Europe. This journey lasted fourteen years and it even took him to northern Africa. During this period, he joined the army in the Austrian-Turkish War, where he became closely acquainted with the conditions in the Military Frontier in Croatia.
Shortly after marrying Anna Rosina Grafenweger in 1672, Valvasor acquired the castle of Bogenšperk/Wagensberg near Litija (Littai), where he arranged a writing, drawing and printing workshop. Valvasor spent a fortune on the publishing of his books; towards the end of his life, his debts forced him to sell Bogenšperk Castle, his vast library and his collection of prints. In 1690, Aleksandar Ignacije Mikulić, the Bishop of Zagreb, bought his library, along with some 7300 graphics, and moved it to Croatia, where the collection became part of the Metropolitana, the library of the Zagreb Archbishopric, now part of the Croatian State Archives.
Valvasor was a pioneer of study of karst phenomena. Upon the proposal of Edmond Halley, who was not only an astronomer but also a geophycsist, and his extensive treatise on the hydrology of the intermittent Lake Cerknica won him a Fellowship of The Royal Society in London. The date of his election according to Bulloch's Roll was the 14th day of December 1687. This is how The Royal Society describes his "career":
"Took part in the Turkish campaign (1663-1664); travelled in France, Italy and Africa; collected books, prints, coins and instruments; started up a copper engraving studio (1678); fought against the Turks (1685)." 
His most important work remains the monumental The Glory of the Duchy of Carniola (original title: Die Ehre deß Herzogthums Crain, Slava vojvodine Kranjske in Slovenian), published 1689 in 15 tomes, totalling 3532 pages and including 528 illustrations and 24 appendices, which provides a vivid description of the Slovenian lands of the time. He also recorded the first written document on vampires when he wrote on the legend of a vampire in Istria named Jure Grando.
Valvasor died in September 1693 in Krško (German: Gurkfeld), and is buried in the family tomb in Izlake.
A collection of Valvasor's copper engravings.
Excellent Valvasor page from Istria on the Net.
Among the rural population in 17th, 18th and 19th centuries a myth about the devil represented by the dormouse shepherd was widespread. The Devil, the dormouse shepherd, clicked, whistled and made a hullabaloo while chasing dormice through the woods.Valvasor was the first to describe dormouse hunting in his great work in 1689, still believing the devil was herding dormice. Even after Steinberg, Hacquet and Kordesh had found an explanation for the myth, that the clicking, whistling and hullabalooing was produced by an owl, even in 1840 the original myth was still deeply held by simple people (KORDESCH, 1840). The myth was the basis for the novel of Josip Jurcic, An Autumn Night Among the Slovenian Dormouse Hunters, published in 1865. It is interesting that the story was still alive after the second world war in the forests of Kocevsko. It is fascinating that even today the myth not only functions as a part of the collective memory of dormouse hunters but is also a typical and very popular Slovenian myth.
In Istria, too, people had to take measures to protect themselves from vampires. The Slovene writer J.V. Valvasor described some of the customs in a 1689 book:
“The people of the Istrian countryside are firmly convinced that sorcerers suck the blood of children. This sucker of blood they call ’strigon’ or ‘vedavec.’ They believe that after his death a ’strigon’ wanders about the village around midnight, knocking at, or striking, doors and that someone will die within days in the house whose doors he has struck. And if someone dies during this period, the peasants insist that the ’strigon’ has eaten him. Even worse is the belief of these gullible peasants that the wandering ’strigoni’ furtively creep into their beds and sleep with their wives without ever letting out a single word. I am particularly concerned about the belief that flesh-and-blood ghosts somehow sneak into the houses and sleep with widows, particularly if they are still young and beautiful. They are so convinced of the truth of all this, that fear will not leave them till they can impale the ’strigon’ with a pole from an ash-tree. With this in mind the bravest, determined to do it, wait until after midnight because before then the ’strigon’ is not in the grave but wanders about. Then they go to the cemetery, open the grave and drive the pole, thick as a fist or a hand, through his belly, disfiguring him horribly. The blood now starts to flow and the body thrashes about as though it were alive and felt the pain. Then they close the coffin , bury it once again and go home.
This practice, of opening a coffin and piercing the corpse with a pole, is not unusual amongst the Istrians of the countryside, that is to say amongst the peasants. Although the authorities impose very severe penalties if they discover it, since it is against religious beliefs, nevertheless it takes place very frequently…”
From: Vampire of Kringa (Deutsch):
"In 1672 there dwelt in the market town of Kring, in the Archduchy of Krain, a man named George Grando, who died, and was buried by Father George, a monk of St. Paul, who, on returning to the widow's house, saw Grando sitting behind the door. The monk and the neighbours fled. Soon stories began to circulate of a dark figure being seen to go about the streets by night, stopping now and then to tap at the door of a house, but never to wait for an answer. In a little while people began to die mysteriously in Kring, and it was noticed that the deaths occurred in the houses at which the spectred figure had tapped its signal. The widow Grando also complained that she was tormented by the spirit of her husband, who night after night threw her into a deep sleep with the object of sucking her blood. The Supan, or chief magistrate, of Kring decided to take the usual steps to ascertain whether Grando was a vampire. He called together some of the neighbours, fortified them with a plentyful supply of spirituous liquor, and they sallied off with torches and a crucifix.
Grando's grave was opened, and the body was found to be perfectly sound and not decomposed, the mouth being opened with a pleasant smile, and there was rosy flush on the cheeks. The whole party were seized with terror and hurried back to Kring, with the exception of the Supan. The second visit was made in company with a priest, and the party also took a heavy stick of hawthorn sharpened to a point. The grave and body were found to be exactly as they had been left. The priest kneeled down solemnly and held the crucifix aloft: "O vampire, look at this," he said; "here is Jesus Christ who loosed us from the pains of hell and died for us upon the tree !"
He went on to address the corpse, when it was seen that great tears were rolling down the vampire's cheeks. A hawthorn stake was brought forward, and as often as they strove to drive it through the body the sharpened wood rebounded, and it was not until one of the number sprang into the grave and cut off the vampire's head that the evil spirit departed with a loud shriek and a contortion of the limbs."
Valvasor also did extensive work on Heraldry.
Valvasor's Opus Insignium Armorumque (1688) is an archive of 2041 coats of arms for notable families in Slovenia and Austria. Valvasor made the drawings, which were painted by artist Bartholomaeus Ramschisslu.