I have always heard that Guru Rinpoche is also Lama Tsongkhapa is that true??? I have yet to find any actual written source saying that, if anyone has do share... it would be interesting to know how all is connected and that the whole sectarianism in Vajrayana is simply a silly creation of mens' ego and limitations not the Buddhas who are all one.
The common findings is that Guru Rinpoche himself prophesied the coming of Je Tsongkhapa... below is an extract from The Berzin Archives:
Both Buddha Shakyamuni and Guru Rinpoche prophesied Tsongkhapa’s birth and attainments. At the time of Buddha Shakyamuni, a young boy who was a previous incarnation of Tsongkhapa presented a crystal rosary to Buddha and received a conch shell in return. Buddha prophesied Manjushri would be born as a boy in Tibet, would found Ganden monastery, and would present a crown to my statue. Buddha gave the boy the future name Sumati-kirti (Blo-bzang grags-pa, Lozang-dragpa). Guru Rinpoche also prophesied a monk named Lozang-dragpa would be born near China, would be regarded as an emanation of a great bodhisattva, and would make a Buddha-statue into a Sambhogakaya representation.
Several indications before Tsongkhapa’s birth also indicated that he would be a great being. His parents, for example, had many auspicious dreams that their child would be an emanation of Avalokiteshvara, Manjushri, and Vajrapani. His future teacher, Chojey Dondrub-rinchen (Chos-rje Don-grub rin-chen), was told by Yamantaka in a vision that he (Yamantaka) would come to Amdo (A-mdo, northeastern Tibet) in a certain year and become his disciple.
Tsongkhapa was born in Tsongkha (Tsong-kha), Amdo, in 1357, the fourth of six sons. The day after Tsongkhapa’s birth, Chojey Dondrub-rinchen sent his main disciple to the parents with gifts, a statue, and a letter. A sandlewood tree grew from the spot where his umbilical cord fell to the ground. Each leaf had a natural picture of the Buddha Sinhanada (Sangs-rgyas Seng-ge sgra), and was thus called Kumbum (sKu-‘bum), a hundred thousand body images. The Gelug monastery called Kumbum was later built on that spot.
Tsongkhapa was not like an ordinary child. He never misbehaved; he instinctively engaged in bodhisattva type actions; and he was extremely intelligent and always wanted to learn everything. At the age of three, he took lay vows from the Fourth Karmapa, Rolpay-dorjey (Kar-ma-pa Rol-pa’i rdo-rje) (1340-1383). Soon after, his father invited Chojey Dondrub-rinchen to their home. The lama offered to care for the education of the boy and the father happily agreed. The boy stayed at home until he was seven, studying with Chojey Dondrub-rinchen. Just seeing the lama read, he instinctively knew how to read without needing to be taught.
During this time, Chojey Dondrub-rinchen gave the boy the empowerments of Five-Deity Chakrasamvara (Dril-bu lha-lnga), Hevajra, Yamantaka, and Vajrapani. By the age of seven, he had already memorized their complete rituals, had completed the Chakrasamvara retreat, was already doing the self-initiation, and already had a vision of Vajrapani. He frequently dreamt of Atisha (Jo-bo rJe dPal-ldan A-ti-sha) (982-1054), which was a sign that he would correct misunderstandings of the Dharma in Tibet and restore its purity, combining sutra and tantra, as Atisha had done.
At the age of seven, Tsongkhapa received novice vows from Chojey Dondrub-rinchen and the ordination name Lozang-dragpa. He continued to study in Amdo with this lama until he was sixteen, at which time he went to U-tsang (dBus-gtsang, Central Tibet) to study further. He never returned to his homeland. Chojey Dondrub-rinchen remained in Amdo, where he founded Jakyung Monastery (Bya-khyung dGon-pa) to the south of Kumbum.