The white stone of the meeting at San Pietro di Castello
Not everyone knows that the church of San Pietro di Castello was until 1807 the cathedral of Venice, while the basilica of San Marco was the private chapel of the Doges.
It was Napoleon who transformed the basilica of San Marco in the most important church in Venice, taking away the title of the church of San Pietro. On the road that leads to the church of San Pietro, a white stone can be seen in the middle of the gray pavement in the Campo San Pietro.
This stone represents the point where the doge and the patriarch of Venice met when the first went to visit the second on the day of June 26 of each year. The patriarch, representative of religious power, met the representative of political power, the doge.
To avoid that the image of political power, going up to the church of Castello, would be less prestigious than the patriarch, who would have to go to the arrival on the boat to receive the doge, (resulting in this way helpful towards political power), was established, a meeting point where they both went on foot.
This point was identified in Campo San Pietro and therefore, in the place where today there is the white stone, the patriarch of Venice went on foot to meet the doge, who came in the same way.
In this way both the powers where on the same level.