Place of building – heart of Klaipėda old town – the most important and beautiful square of the town. Reconstructed building is in very important place of this square – intersection of Theatre’s square and Turgaus street. The building consists of two parts – old neo-renaissance part built in 1858 and extension built after the Second World War. All the time till now it was bank buildings. The old neo-renaissance bank complex (bank’s block and its belongings) took the whole small quarter, the limits of which have remained up to now. The building were moved away a bit from the Theatre square and in the vacant place was made a small square.Designers paid the biggest attention to the main elevation (in Turgaus street) and back elevation (in Theatre square). In the beginning of 20 century the main door was moved to the side, which is looking to the Theatre square. After the Second World War the extension that was built next to the back elevation blocked off the main door, caused damage not only to looks of the building, but also to harmony of the whole Theatre square. Some later reconstructions of the new building did not improve the situation – this foreign body had not incorporated into harmonious wholeness of old architecture. Therefore, all previous attempts of architects to create balance in old town’s architecture were not successful. As a result, when forming new look of the building at the mean time, it was seek to create radical change in the environment. Newly created character of the building was not indifferent to the environment – neo-renaissance part of the building was fairly involved into radical changes. We named this process as a concept “architectural diffusion”.