The originally Gothic chapel dedicated to the Assumption was funded by Casimir Jagiellonczyk. It served the royal family when it resided in the city's Lower Castle, while the crypt provided a burial site for the Jagiellonians, including the Royal Prince St. Casimir and king Alexander Jagiellonczyk. During the reigns of Sigismund I and Sigismund Augustus, the chapel was enlarged and restored at royal expense. In connection with the rising cult of Casimir-Prince, Sigismund III Vasa initiated efforts to have the chapel restored in preparation for the former's canonisation. Changing political circumstances in the Poland-Lithuania and rising status of Vilna led to the building of a more richly decorated chapel dedicated to St. Casimir, begun around March, 1623 (according to archivised documents), linked directly to the neighbouring Lower Castle (recently 'reconstructed'). To carry out the design, Sigismund employed both local artists (e.g. Piotr Nonhardt), while Constante and Jakub Tencalla were its main executors, while a long list of sculptors and painters were employed for interior decoration. Detailed information also exists on materials used on the main construction. For Sigsmund III Vasa it was important to emphasise the Roman character of the architecture; hence emphasised references to Roman Baroque architecture and that of the Papacy in particular.