Kanonia i mury obronne przy ul. Ostrów Tumski 11 w Poznaniu. Nowe ustalenia naukowe

The canonry building at 11, Ostrów Tumski Street in Poznań is situated on the western side of Ostrów. A one-floor building on the plan of an extended rectangle, with a tall, hip roof. The subject of defensive walls and canonries has been explored by many researchers since early 19th century. Those who wrote about them included Józef Łukaszewicz in 1838, the priest Józef Nowacki in 1959, Izabela Jasiecka and Henryk Kondziela in 1965, Eugeniusz Linette in 1983, Konrad Lutuński, Piotr Budzian and Alicja Karłowska-Kamzowa in 1990, Antoni Kąsinowski in 2005, Tomasz Ratajczak in 2008. All of them related both investments to the activity of Bishop Lubrański in the 16th century. It was only Professor Hanna Kočka-Krenz who, in 2006, posed a thesis that the construction of the walls had begun earlier. The architectural research conducted in 2014 by Jerzy Borwiński – in consideration of the fact that the elevation has recently been plastered – was limited to some parts of the interior of the building. After the examination of the roof structure, it was found that the carpenter’s marks in the southern and northern part are made in different systems and that the two, edge top trusses are missing. The research has shown that the present architectural form of the building of Ostrów Tumski 11 canonry in Poznań is a result of the construction modifications in the 18th, 19th and 20th centuries. In the main, those modifications involved adopting the structure of a much older Gothic construction. The most important conclusions drawn out of the research are as follows: the longer, western wall of the building rested on a former defensive wall. The Gothic structure had vertical gables topped triangularly or step-like, in the Gothic convention. The windows in the Gothic building had an axis layout different from the present window openings from the 18th century. There were profiled, beam ceilings over all rooms of the Gothic part of the building. It was determined that the major development of the canonry was in the 19th century, when the northern part of the building was added. The evidence of that is a seam in the walls of the ground floor, block threads of the brick walls, dendrochronological dating of the roof structure, as well as chamfered ceilings over the ground floor, typical of that period. In the dating of the Gothic canonry examined in 2014, in addition to many new discoveries, the complex examination of the roof structure was of a high importance. It was found that there are two completely independent structures on the building. It was confirmed by the conducted dendrochronological analysis of the samples of wood. The wood used in the southern (Gothic) structure was made of the pines cut down in 1476. On the other hand, the wood used in the northern structure comes from the wood of the same type cut down in 1749 and 1750. The Gothic structure of the canonry was made in queenpost structure with lying queen posts. Such systems became popular in our area as late as in the 16th century. Thus, it is possible that we are dealing with a pioneer solution in the territory of Poznań. Consequently, the history of constructions of defensive walls in Ostrów Tumski and the activity of Bishop Jan Lubrański, who did not begin the investment, but only continued the work of his predecessors.