But Peter not only made new military preparations, but prosecuted his schemes of internal improvement, and projected, after his unfortunate defeat at Narva, the union, by a canal, of the Baltic and Caspian Seas. About this time, he introduced into Russia flocks of Saxony sheep, erected linen and paper manufactories, built hospitals, and invited skilful mechanics, of all trades, to settle in his kingdom. But Charles thought only of war and glory, and did not reconstruct or reproduce. He pursued his military career by invading Poland, then ruled by the Elector of Saxony; while Peter turned his attention to the organization of new armies, melting bells into cannon, constructing fleets, and attending to all the complicated cares of a mighty nation with the most minute assiduity. He drew plans of fortresses, projected military reforms, and inspired his soldiers with his own enthusiasm. And his energy and perseverance were soon rewarded. He captured Marianburgh, a strong city on the confines of Livonia and Ingria, and among the captives was a young peasant girl, who eventually became the Empress Catharine, and to whose counsels Peter was much indebted for his great success. She was the daughter of a poor woman of Livonia; lost her mother at the age of three years; and, at that early age, attracted the notice of the parish clerk, a Lutheran clergyman: was brought up with his own daughters, and married a young sergeant of the army, who was killed in the capture of the city. She interested the Russian general, by her intense grief and great beauty; was taken into his family, and, soon after, won the favor of Prince Menzikoff, the prime minister of the czar; became mistress of his palace; there beheld Peter himself, captivated him, and was married to him,--at first privately, and afterwards publicly. Her rise, from so obscure a position, in a distant country town, to be the wife of the absolute monarch of an empire of thirty-three millions of people, is the most extraordinary in the history of the world. When she enslaved the czar by the power of her charms, she was only seventeen years of age; two years after the foundations of St. Petersburg were laid. [Sidenote: Building of St. Petersburg.]