The fall of Amalfi and Salerno to Robert Guiscard were influenced by his wife, Sichelgaita. Amalfi probably surrendered as a result of her negotiations, and Salerno fell when she stopped petitioning her husband on behalf of her brother (the prince of Salerno). The Amalfitans unsuccessfully subjected themselves to Prince Gisulf to avoid Norman suzerainty, but the states (whose histories had been joined since the 9th century) ultimately came under Norman control.