James Knox Polk (November 2, 1795 – June 15, 1849) was the 11th president of the United States, serving from 1845 to 1849. He previously was Speaker of the House of Representatives (1835–1839) and governor of Tennessee (1839–1841). He was the first of 10 children born into a family of farmers. His mother Jane named him after her father, James Knox. Dispatches from Slidell and from the U.S. consul in Mexico City, John Black, made clear their views that U.S. aims for territorial expansion could not be accomplished without war.Taylor's instructions were to repel any incursion by Mexico north of the Rio Grande, when the Texas boundary line had been de facto at the Nueces River. Initially, his army did not advance further than Corpus Christi, at the mouth of the Nueces.