Ancient Greek and Roman civilisations introduced essential innovations in watermill technology. Water wheels and gear trains existed in ancient Greece back in the 3rd century BC. In the first century BC, Romans used vertical water wheels that replaced horizontal ones invented by Greeks. The latter innovation led to one of the major breakthroughs in watermill technology, the introduction of a tooth gear. The new solution allowed for the conversion of the vertical rotation of a millwheel into the horizontal rotation of quern. It was around that time that three types of millwheels became dominant. The first type is a wheel rotated by water running underneath it (the one that uses kinetic energy of water); the second-type wheel is driven by water running from above, while the third type rotates because water runs into the middle of the wheel (both of them use potential energy of water). The structure of watermills remained almost unchanged until the early 20th century. In the Early Middle Ages, people forgot many inventions of the ancient world. Nevertheless, watermill technologies started spreading swiftly across Western Europe and further into the East since around the 11th century. Monks, especially Cistercians (members of the Catholic order established in 1098 in France) were among active propagators of watermills in the Middle Ages.
Lithuanian rivers "harnessed"
There is no reason to question the arrival of the watermill technology in Lithuania from the West, because first watermills emerge in historical documents only after the Christianisation of the country. The introduction of watermills apparently took place in several directions. Historical sources first refer to watermills in Lithuania in 1404 when King of Poland Jogaila and Grand Duke of Lithuania Vytautas signed the Treaty of Raciąż with the German Order allowing it to build watermills on both sides of Nevėžis, the river in Samogitia that was then run by the German knights. We do not know whether the German Order, which ruled Samogitia until 1409, was able to make use of that permission. Even if the knights had built several mills, they probably were put out of operation because no historical source ever mentions them. The earliest information about functioning watermills in the Grand Duchy of Lithuania dates back to the end of Vytautas' reign. On the 31st of January 1429, after the congress in Lutsk, Vytautas granted his miller Petr Luba (Petri Luba molendinatoris nostri Lucensis) the lifelong privilege of running the local mill and receiving income from it. The text of the privilege says that Petr has built the mill and the bridge at his own expense. The miller of Lutsk apparently was born in Masovia, therefore it is likely that he used the Masovian-type construction for his mill. The privilege also refers to the bridge and embankments indicating that the mill was built lower than the dam. This way or the other, the bridge stood over the dam.
Historical sources of the GDL from the second half of the 15th century and the first half of the 16th century increasingly refer to watermills, although they almost never provide any details. The nobility used to mention watermills in documents related to sale or settlement of their lands. These acts indicate that watermills were more common in the western part of the GDL (excluding Samogitia) where large areas belonged to wealthy nobility, dukes and the Church. Landowners were obviously interested in protecting their property, therefore operation of mills was regulated by law. The First Lithuanian Statute (1529) declares in the eleventh paragraph of the eighth chapter: "In the event when anyone's land includes a river, that is both banks of the river, and if he builds dams and mills and inundates his neighbours' mills located up the stream, he must (...) lower the level of water in his dams and reimburse the inundated person in accordance to the evidences provided by him."
The provisions of the Statute lead to the notion that the word "mill" could only mean a watermill at that time. People used to build watermills by rivers, lakes and ponds. To keep water high in ponds and rivers, they would construct dams and reinforce natural banks. Every dam featured a narrow passage for water that rotated one or more mill wheels either by falling onto them or by running below them. Wood was used to build mills and dams. It is not a coincidence that the Statute included a regulation under which a mill could be burned down and a dam could be destroyed using axes under certain circumstances. The 1551 income register of the parson of Pasvalys is a unique document that provides some details about the operations of the local mill depending on a season. The mill usually started business in April, after river ice was gone. It had to halt operations for a considerable period of time during hot and dry summers when the level of water lowered due to the lack of rain and mill wheels stood idle.
Querns moving slowly
From the middle of the 16th century, historical sources offer a more detailed information on the equipment used in watermills, because the country's agriculture almost entirely turned to grain cultivation in the wake of the land reform. Despite the transformation, the watermill network was expanding slowly and the technical improvement of the sector was slow. Long winters, dry summers, scarce crops, poor communications and low domestic consumption were the key obstacles hindering the progress. In these circumstances, Lithuania was not able to make the utmost use of the benefits that watermills offered. This is why property inventories from Lithuanian estates mention hand querns more often than watermills even in the second half of the 16th century. Even when the inventories describe watermills in detail, one can have the impression that those installations were not considered valuable.
Here's a description of a mill in the estate of Graužai, near Kelmė, from the property inventory of 1595: "There is a dam next to the mansion ... on (the bank of) River Vilbėnas, and there is a mill too, but the old main building is rotten (!) and completely empty; water valleys are rotten as well, mill wheel destroyed, the whole (building) in ruins. To form a pond, there is a dam. Everything needs repair." The description shows that people of that time would make a clear distinction between a mill and its main building, therefore the key milling equipment was not necessarily inside it.
Mill wheel and quern were the most valuable installations of a mill; they often appear in property inventories. No other wooden pieces of equipment, such as shafts, gears and valleys, have ever been singled out in these documents. In technical terms, though, each of them was a rather sophisticated part that could be improved and could be made employing different technologies. Unfortunately, we know very little about that.
Lithuanian sources say nothing about the most widespread types of mill wheels, but historians cite documents describing similar mills in Poland to presume that two types of mill wheels were most popular in the GDL: the wheel rotated by water running underneath it (Polish: koło walne, koło podsiębiernie) and the wheel rotated by water falling onto it (Polish: koło korzecznie, koło nasiębiernie). The first type is more ancient, according to historians. The latter one was spreading in Poland since the early 16th century but did not supplant the first one. From the 16th century through the 18th century, both types of wheels were used and sometimes in the same mill. There is no reason to think that the situation was different in Lithuania. For instance, the plan of Vilnius in the atlas by Georg Braun, features a watermill with the main wheel moved by the water of River Neris streaming beneath it. On the other hand, the fact that water valleys feature in some inventories is an indirect indication that people also used wheels rotated by falling water.
Stone-made quern was another sophisticated installation of a watermill. It consisted of two quern-stones, the lower stationary and the upper mobile rotated by a mill wheel. Some historians believe that people in the GDL imported oldest quern for watermills before starting to produce them locally. To support their theory, historians refer to Lithuanian place names related to quern (girnos), such as Girnakaliai, Girnikai, Girninkai, Girniūnai, Girkaliai. It is difficult to say whether they still existed in the middle of the 16th century.
The last technical obstacles that prevented the development of watermill network in the GDL were removed when local people learned to produce watermill equipment using local materials. Unfortunately, we have no accurate list of watermills in the GDL between the 16th and 18th century. The 1777 lustration (list) of watermills is probably the most accurate document, but the information from many districts is missing. Historians guess that about 4,000 watermills operated throughout the GDL at that time and about 1,200 of them were built in the territory of the present-day Lithuania. Considering the size of the network, it is very likely that the major part of it came into being before the harsh upheavals of the mid-17th century.