Dorje Shugden arose specifically to protect the teachings and legacy of Lama Tsongkhapa's tradition. So what did Lama Tsongkhapa left behind? You can read here in brief what did Lama Tsongkhapa leave behind....
Legacy
Bronze depicting Tsongkhapa, who is known and revered by Mongolians as Bogd Zonkhov.
With the founding of the Ganden monastery in 1409, he laid down the basis for what was later named the Gelug ("virtuous ones") order. At the time of the foundation of the Ganden monastery, his followers became to be known as "Gandenbas." Tsongkhapa himself never announced the establishment of a new monastic order.[3] Tsongkhapa’s teachings drew upon the teachings of Atisha, emphasizing the study of Vinaya, the Tripi?aka, and the Shastras. Atisha’s Lamrim inspired Tsongkhapa’s Lamrim Chenmo, which became a main text among his followers. He also practised and taught extensively the Vajrayana, and especially how to bring the Sutra and Tantra teachings together, wrote works that summarized the root teachings of the Buddhist philosophical schools, as well as commentaries on the Pratimoksha, Prajnaparamita, Candrakirti’s Madhyamakavatara, logic, and the Sarma Tantras. Tsongkhapa emphasised a strong monastic Sangha. Furthermore, he promoted the study of logic, encouraged formal debates as part of Dharma studies, and instructed disciples in the Guhyasamaja, Kalacakra, and Hevajra Tantras.
Tsongkhapa was one of the foremost authorities of Tibetan Buddhism at the time. He composed a devotional prayer called the Migtsema Prayer to his Sakya master Rendawa, which was offered back to Tsongkhapa, with the note of his master saying that these verses were more applicable to Tsongkhapa than to himself. After Tsongkhapa's passing away, several biographies were written by Lamas of different traditions, and they all agreed that he was a teacher without parallel. The 9th Karmapa, Wangchuk Dorje, praised Tsongkhapa as one "who swept away wrong views with the correct and perfect ones." The 8th Karmapa, Gyalwa Mikyö Dorje, wrote in his poem In Praise of the Incomparable Tsong Khapa:
When the teachings of the Sakya, Kagyue, Kadam
And Nyingma sects in Tibet were declining,
You, O Tsong Khapa, revived Buddha's Doctrine,
Hence I sing this praise to you of Ganden Mountain.
Further, it is said that the Buddha Sakyamuni spoke of his coming as an emanation of the Bodhisattva Manjusri in the short verse from the Root Tantra of Manjushri (Tib. 'Jam-dpal rtsa-rgyud):
After I pass away
And my pure doctrine is absent,
You will appear as an ordinary being,
Performing the deeds of a Buddha
And establishing the Joyful Land, the great Protector,
In the Land of the Snows.
Although Tsongkhapa would finally pass away in 1419 at the age of sixty-two, he left to the world 18 volumes of collected teachings, with the largest amount being on Guhyasam?ja tantra. These 18 volumes contain hundreds of titles relating to all aspects of Buddhist teachings and clarify some of the most difficult topics of Sutrayana and Vajrayana teachings.
Major works among them are:
The Great Exposition of the Stages of the Path (lam rim chen mo),
The Great Exposition of Tantras (sngags rim chen mo),
The Essence of Eloquence on the Interpretive and Definitive Teachings (drang nges legs bshad snying po; full title: gsung rab kyi drang ba dang nges pai don rnam par phye ba gsal bar byed pa legs par bshad pai snying po),
The Praise of Relativity (rten ’brel bstod pa),
The Clear Exposition of the Five Stages of Guhyasamaja (gsang ’dus rim lnga gsal sgron) and
The Golden Rosary (gser phreng).
These scriptures are the prime source for the studies of the Gelugpa tradition and these and other teachings of Tsongkhapa endured into the modern age and are seen as a protection against misconceptions in Mahayana and Vajrayana Buddhism.
The 14th Dalai Lama has highlighted the fidelity of Tsongkhapa's work to the meaning found in Buddhapalita’s work. Tsongkhapa’s work is praised as being profound and true to tradition, essentially a clarification and condensation of the transmitted teachings, which after all, are intended to encapsulate unchanging truth.
After Tsongkhapa had founded the monastery of Ganden in 1409, it became his main seat. He had many students, among whom Gyaltsab Dharma Rinchen (1364–1431), Khedrup Gelek Pelzang (1385–1438), Togden Jampal Gyatso, Jamyang Choje, Jamchenpa Sherap Senge, and the first Dalai Lama, Gyalwa Gendün Drup (1391–1474), were the most outstanding. After Tsongkhapa’s passing his teachings were held and kept by Gyaltsab Dharma Rinchen and Khedrub Gelek Pälsang. From then on, his lineage has been held by the Ganden Tripas, the throne-holders of Ganden Monastery, among whom the present one is Thubten Nyima Lungtok Tenzin Norbu, the 102nd Ganden Tripa.
After the founding of Ganden Monastery by Tsongkhapa, Drepung Monastery was founded by Jamyang Choje, Sera Monastery was founded by Chöje Shakya Yeshe and the Gendün Drup founded Tashilhunpo Monastery. Many Gelug monasteries were built throughout Tibet but also in China and Mongolia. He spent some time as a hermit in Pabonka Hermitage, which was built during Songsten Gampo times, approximately 8 kilometres north west of Lhasa. Today, it is also part of Sera.
Among the many lineage holders of the Yellow Hat Tradition (Gelugpas) there are the successive incarnations of the Panchen Lama as well as the Chagkya Dorje Chang, Ngachen Könchok Gyaltsen, Kyishö Tulku Tenzin Thrinly, Jamyang Shepa, Phurchok Jampa Rinpoche, Jamyang Dewe Dorje, Takphu Rinpoche, Khachen Yeshe Gyaltsen, Trijang Rinpoche, Domo Geshe Rinpoche,[9] and many others.
The annual Tibetan prayer festival Monlam Prayer Festival was established by Tsongkhapa. There he offered service to ten thousand monks. The establishment of the Great Prayer Festival is seen as one of his Four Great Deeds. It celebrates the miraculous deeds of Buddha Shakyamuni.
