Latö (la stod) is the western part of Tsang (gtsang). According to legend, a descendant of Yapang Khön-bar-kyé, Könpa Jégungtak, was told by King Trihsong Détsen to establish a homeland for his clan and Könpa Jégungtak did so at Nyentsé-tar. Thus, the region was strongly associated with the imperial power at Samyé. Regardless of the veracity of the legend, it is likely that the Khön clan were “minor aristocracy” during the royal dynastic period and controlled the area of Latö. (Davidson, 269-270).
Latö is mentioned throughout the Blue Annals and it is clearly a region of great importance as it is associated with many important figures such as Dharmabodhi ('dzeng), Pakpa ('phags pa), Śākyaśrī, and Milarepa (mid la ras pa) among many others. It is mentioned in reference to births, deaths, travels, and education. However, there are occasions in which it is apparently referred to in a negative manner. For example, Gyalwa Götsangpa Gönpo Dorje (rgod tshang pa mgon po rdo rje, 1189-1258) requested permission from the Dharmasvāmin Wön (dbon) to go to Latö and had to convince him to grant permission. Ultimately, the latter agreed and said, "Well, go now! If you can spread your Teacher's doctrine in a heathen country, great would be the benefit!" (Roerich, 684). Similarly, the Bodhisattva Kunga (kun dga’) tells Patsap (pa tshab) that there is no one in Latö who was able to “taste” the “salt” of teachings that he possessed (Roerich, 926).
Sources
The Blue Annals
Davidson, Tibetan Renaissance