Cardinal Alessandro Farnese, being the sole patron of the Il Gesù, wanted the floor plan to be created by Giacomo della Porta. Porta designed the church using a Latin cross plan. This type of plan is characterized by a transept intersecting the nave, forming a cross-like shape when viewed from above.
Architectural Terms
Dome - a rounded vault forming the roof of a building or structure, typically with a circular base
Nave - the central part of a church building, intended to accommodate most of the congregation. In traditional Western churches it is rectangular, separated from the chancel by a step or rail, and from adjacent aisles by pillars.
Transept - (in a cross-shaped church) either of the two parts forming the arms of the cross shape, projecting at right angles from the nave.
Fresco - a painting done rapidly in watercolor on wet plaster on a wall or ceiling, so that the colors penetrate the plaster and become fixed as it dries
Pilaster - a rectangular column, especially one projecting from a wall
Stucco - fine exterior or interior plasterwork used as three-dimensional ornamentation
Gilding - the material used in, or the surface produced by applying gold leaf or gold paint
Façade - the face of a building, especially the principal front that looks onto a street or open space
Entablature -a horizontal, continuous lintel on a classical building supported by columns or a wall, comprising the architrave, frieze, and cornice
Pediment - the triangular upper part of the front of a building in classical style, typically surmounting a portico of columns
Corinthian - characterized by a slender fluted column having an ornate flared capital decorated with acanthus leaves
Flying Buttress - a masonry structure that typically consists of a straight inclined bar carried on an arch and a solid pier or buttress against which it abuts and that receives the thrust of a roof or vault