Focus on this artwork and discuss the Location.
The Frari is a very large Gothic church of the early 15th-century, initially plainly built of brick, like many Franciscan churches designed for preaching to large crowds, but now filled with elaborate tombs and paintings.  Titian himself is buried there, though this is an unintended result of the chaos of the plague that killed him, with a large 19th-century monument that includes a relief version of the Assumption.
The high altar is a very long way from the nave, and the view of it is restricted by an elaborate stone choir-screen of 1475, with a round-headed arch in the centre, and a pulpit at each end. Immediately behind this, across about half the width of the church, is the choir, with rows of choir-stalls facing each other, and a high wooden backing.  After this comes a wide but shallow area, reaching into the transepts, before the chancel in the apse, which is very deep.  The rounded top of the painting allows it to be framed neatly by the choir-screen arch for a viewer standing at the central axis of the church even at the back of the nave, though from there it appears tiny.  It also allows the rounded circle of heavenly light to complete the top of the composition, with no awkward corners to fill.
The high altar and its elaborate reredos framing the altarpiece was probably designed in its broad conception by Titian, to match his painting.  The detailed design and execution was probably by Lorenzo Bregno. The painting is framed by an extension of the altar in marble and gilding, which matches not only the round top of the choir-screen arch, but (in broad terms) the scrolling decoration around it.  The classical style, with large columns on either side, inevitably clashes somewhat with the Gothic style of the architecture, but efforts have been made to minimize this by aligning the levels of elements of both frame and painting with the zones of the architecture.  For example, the top of the cornice of the frame is (depending on the viewing position) broadly the same as the level of the bottom of the third tier of windows.
apse Titian Lorenzo Bregno choir cornice altarpiece relief choir-screen chancel pulpit Frari reredos transept