Historical province of Pangasinan, created in 1580 by Governor General Ronquillo de Penalosa, was among the earliest political and administrative units in the Philippines. It was officially conquered and colonized by D. Martin Goiti in 1571. At that time, its territorial jurisdiction extended to the present province of Zambales and parts of La Union and Tarlac. By the middle of the 19th century, however the northern towns of Agoo to Bacnutan were separated from the province and became parts of La Union. The Provincial territory was furthered diminished in 1875 with the annexation of Paniqui and other tows south of it to Tarlac.