When did Troy-Hittite relations start?

We learn about the role of Wilusa in Hittite history from the text called the Alaksandu Treaty, a text which was known since 1907, but published in 1920 and interpreted in 1922-24. This treaty was concluded in 1280 B. C. E. between the Great Hittite King Muwattali II (1290-1272 В. C. E) and Alaksandros, king of Wilusa. Its content also illuminates the past of the Hittite-Wilusa relationships. In the treaty, the following lines deserve our attention:

"My predecessor used to have political politic rule over all of Arzawa and Wilusa countries. Because of this the Arzawa country later on declared war; regardless, I know that this goes way back and no king of Hattusa country has ever lost against the Wilusa country. Although the Wilusa country has lost to Hattusa country, they used to be friends with the Hattusa kings and they regularly sent messengers back and forth."

In this twenty-paragraph text, it is stated that the Wilusa King who has been referred to as Alaksandu twenty three times, is the successor of Kukkuni. This king of Wilusa Kukkuni, is good friends with Muwattali's grandfather the Great King Suppululiuma I (1355-1320 B. C. E.), and they sent messengers back and forth. Suppiluliuma I is at the same time, the great grandson of the Great Hittite King Tudhalija I (1420-1400 В. С. Е.). About him, it is stated that "Wilusa country was friends with him and used to send messengers regularly to him." If the text of Alaksandu Treaty was written in 1280 В. С. Е., then it goes back a hundred and forty years prior to the friendship treaties that were concluded between the Hattusa Kingdom and the Wilusa Country. In fact, the aforementioned relations go even further back, because the founder king that is supposed to honor the agreement indicates the period before 1600 B. C. E. in Hittite history. For this reason, at the time when Alaksandu Treaty was signed, relations with Wilusa had already a history of three hundred and twenty years from the point of view of the Hittites.