The Livonian Chronicle of Henry (1184-1227) is the most ancient written document where the name of the Salaca river was mentioned as early as 1216. It also reveals the fact that in the early 13th century vessels went as far as Burtnieks lake:

XIX.11.: "When the grand duke died, the news of it reached Saaremaa, and at the instance when the men of Saaremaa learned that the Daugava port was guarded by rangers and armed men, down the Salaca they went and looted the Latvian villages around Burtnieks lake, captured the women and killed the men. Then some Latvians convened and followed them; they captured and killed some of the invaders, the others were forced to retreat to the ships."

The same text in Latin: Mortuo itaque rege pervenit verbum in Osiliam, simul et audientes balistarios et viros armatos Dune portum custodire, Saletsam intraverunt et ascendentes circa stagnum Astegerwe m villas Lettorum despoliaverunt et mulieres capientes viros interfecerunt. Et congregati sunt quidam ex Lettis, insequentes eos et com prehensos quosdam interfecerunt n et alios ad naves fugaverunt.

The first reference to the Salaca, however, dates back to 1215, when German crusaders having united with the Livonians and Latvians (Livs and Lettens) went to Ridala (a maritime region in the South of Haapsalu) past the Salaca through Sontagana area (nowadays - Pärnu district). The road, which was described by the chronicler Henry and along which the troop was moving, led along the sea and partly coincided with the current Riga - Pärnu road:

XVIII 5. There were about three thousand of our men: Germans and just as many Livs and Lettens. And they kept their way walking on the sea ice past the Salaca until they reached the place they wanted to, namely Ridala.

The same text in Latin: Et [erant] ex nostris circiter tria milla Theuthonicorum et Lyvonum et Lettorum alia todiem. Et ibant in glacie maris, pretereuntes Saletsam, donec venirent quo desiderabant, scilicet in Rotaliam.