sentences:  The first part of the Keizersgracht, between Brouwersgracht and (approximately) the current Leidsegracht, was dug in the summer of 1615 at the initiative of mayor Frans Hendricksz.Oetgens, city carpenter Hendrick Jacobsz Staets and city surveyor Lucas Jansz Sinck.The Keizersgracht was named after Maximilian I, Holy Roman Emperor.