San Salvador
Giorgio Spavento and Tullio Lombardo 1506-34

History
Traditionally said to have been one of the churches built, this time in 639, by San Magno (Saint Magnus), to whom the Saviour (Salvatore) had appeared in a dream and sent him a sign - a red cloud this time. The first documented date is 1067. This church is said to have had an iron-grating floor with running water beneath. A rebuilding after the fire of 1106 can be seen on De Barbari's famous map of 1500. It is in the porch of this Romanesque church that Pope Alexander III is said to have taken refuge disguised as a pilgrim and fleeing Emperor Frederic Barberossa. (But another story has him working for six months in the kitchen of the convent of  Santa Maria della Carità.) From 1267 San Salvador housed the relics of the first patron of the city, Theodore, which had previously been in San Marco. 
The present Renaissance church was begun in 1506 to designs by Giorgio Spavento, with Tullio Lombardo supervising, helped by his father Pietro, following Spavento's death three years after work began. The church was largely completed around 1523, with Jacopo Sansovino responsible for the completion of work from 1530-34 and for the lovely frescoed side entrance onto the Mercerie. The façade was rebuilt 1649-63 to a design by Giuseppe Sardi with sculptural decoration by Bernardo Falcone. It has an Austrian cannonball somewhat neatly embedded in the bottom left hand corner.

The interior
The church is monumental with a lovely dark grey interior, reminding me of some favourite churches in Florence, although the multiple-domed interior is supposed to hark back to the Byzantine and to San Marco. Despite the darkish stone it's a well-lit church. The interior is designed on mathematical principals, based on the proportion of 2:1 - square bays alternating with half-bays.
The remains of Saint Theodore, Venice's original patron saint, are in the chapel to the right of the apse.
The body of the church is

because that was evidently the organ through which the holy spirit (specifically The Word) entered and impregnated her.
The other great Titian is another late one - the damaged but explosive and impressive Transfiguration of 1560 over the high altar, which hides a 14th century silver-gilt reredos revealed only at Christmas, Easter and at the feast of The Transfiguration on the 6th of August. A pulley lowered the painting on feast days and the canvas had suffered from this rough use and had been nastily over-painted to hide damage. Restoration in 1997 revealed the true Titian, painted to work in its unique situation. The Pala d'Oro reredos was itself restored in 2010. It too centres on the Transfiguration, the crucial event in Christ's becoming the Saviour, as commemorated in the name of this church. It has full- and half-length figures of saints in the two main registers of its five rows - the first and fifth are of a later date.  The full-length saints either side of the central panel include Saint Augustine, whose rule was followed by the monks here, along with Saints Theodore (whose relics are here) and Mark, the patron saints of Venice.
A third Titian, a Crucifixion, was commissioned by Flemish merchant Giovanni D'Anna for his family altar right opposite the Cornovi chapel. The D'Anna family suffered financially following Giovanni's death, however, and work on the chapel halted. The Crucifixion is lost, or may indeed never have been painted. The commissioners of these three paintings and Titian himself were all members of the Scuola Grande di San Rocco and there is a possibility that it was a co-ordinated commission.
Then there's The Supper at Emmaus (see below) a somewhat stiff piece of work which tradition ascribed to Giovanni Bellini, or a pupil of Bellini called Benedetto Diana (according to Layard) or Carpaccio (according to Crowe and Cavalcaselle) or to Bellini's

There are also works by Paris Bordone, Palma Giovane (The Virgin of the Carmelites appearing to Saints Anthony Abbot, John the Baptist, and Francis of Assisi, on the altar of the Luganegheri) and, on the inside of the organ doors, two paintings by Franceso Vecellio, Titian's brother, who is also said to be responsible for the frescoes in the side entrance. The sacristy supposedly has more frescoes by him, discovered in the 1920s and restored in 2003.

Lost art
Two very early Bellinis, a Crucifixion and a Transfiguration, both still looking very indebted to Mantegna (and both in the Correr Museum) may have been painted for San Salvador, the latter for over the high altar - it may have come from here or San Giobbe, as both churches are recorded as having had a Bellini depicting this scene, and the painting has a quotation from the Book of Job on a cartellino.
A Giambattista Tiepolo altarpiece depicting four saints, painted for the Cornaro family for the right transept's right-hand altar, was destroyed in a fire.

Campanile 23m (75ft) mechanical bells
De Barbari's map shows a chunky detached tower that was a 14th-century renovation of the original. Restoration in 1881 saw the tower raised and the shaky structure had its foundations broadened in 1903 and 1911.

The church in art
Canaletto, Campo San Salvador, around 1736, Private collection, London. (see below)

The monastery
The attached Augustinian monastery, with its restored cloisters (entrance to the right of the church facade) is said to be Sansovino's work too. Suppressed by Napoleon in 1810, it is now the HQ of a phone company and is open Tues-Sun 10am-6pm.

Marin Sanudo wrote
Friday 25th was the day of the Annunciation to our Lady. On this day in 421 the city of Rialto was founded and the first stone laid, on which day - according to Saint Augustine - the world was created and the Lord Jesus Christ was crucified. On this day in 1507 the first stone for the new building of San Salvador was laid. Thus this is a very great feast day.

Ruskin wrote
In the interior of the church are some of the best examples of Renaissance sculptural monuments in Venice. It is said to possess an important pala of silver, of the thirteenth century, one of the objects in Venice which I much regret having forgotten to examine; besides two Titians, a Bonifazio, and a John Bellini. The latter ("The Supper at Emmaus") must, I think, have been entirely repainted: it is not only unworthy of the master, but unlike him; as far, at least, as I could see from below, for it is hung high.

Opening times
Monday-Saturday: 9.00-12.00 and 3.00-6.00,
Sunday: 3.00-7.00
The afternoon hours are shorter (4-6 pm) in the summer (June-August).
Scaffolding update November 2019 In July 2018 there was a high fence all along the façade with a canopy over over the entrance. This accident-prevention construction has now been replaced by massive all-over scaffolding covering the façade and the monastery façade to the right, and there's a huge sticking-out column of scaffolding with advertising, so work is presumably progressing.

The church has a website  which used to block access if you were using an adblocker, a very strange thing for a non-commercial site to do, and now seems to just provide links to £200 walking tours, no matter which button you click. What was I saying about non-commercial...

Vaporetto Rialto

map

The campanile by Ferdinand Ongania in the 19th century.