to Finland is a papal letter in 1229. During the Swedish rule of Finland that followed, foreign horses obtained by the Finnish cavalry, whether purchased for replenishment or seized as spoils of war, probably influenced the Finnish horse population. The first significant, planned efforts to improve the quality of horses through selective breeding in Finland occurred in the 16th century, when Gustav Vasa, known for his interest in horse breeding, founded mare manors (), stud farms, on his properties in Western Finland. He ordered the importation of larger horses from Central Europe, mainly from the region of Friesland. These horse were brought to Sweden and probably into Finland as well. The imports were kept at regional royal farms (, literally, "King's estate") to service local mares. In a letter from 1556, Gustav Vasa mentions that there were 231 breeding horses of this kind in Finland. It is not known whether these horses were imported directly from Central Europe to Finland, or descended from imports brought first to Sweden. Friesian stallions were used in Finland early in the 16th century to increase the size of the Finnish horse, and were employed for breeding in the royal farms up until the 1650s. Gustav Vasa also carried out major reforms of his cavalry. After the decline of heavy cavalry in the Late Middle Ages, light cavalry was gaining importance, and with it a new approach to horse breeding. In 1550, he gave orders that "stud manors" () be founded on royal farms (Sw: kungsgård), not only in Sweden but also in every municipality of Finland. These studs were to each hold 20 mares and a smaller number of stallions, both Finnish horses and horses imported from Sweden. Gustav Vasa also imported mares from the lands bordering the North Sea; most likely of a Friesian type. His goal was to increase the size and weight of the Finnish horse population. His successor, Eric XIV prohibited the exporting of Finnish horses, which demonstrated the success of these efforts as well as the importance of the horses of the region of Finland. The horse breeding farms lasted only for about 100 years under later rulers of the Vasa line before the programs deteriorated. The last of the stud manors, that of Pori, was closed in 1651, and the crown-owned stallions and mares of the Pori stud were transported to Gotland. Outside of these breeding efforts, Finnish