The Mandyam Iyengers were masters of Sanskrit. They spoke a distinct dialect of Tamil called Mandyam Tamil.

All the Mandyam Iyengars belonged to the Thenkalai sect of Iyengars. It was time of the last Anglo-Mysore war between Tipu on one hand and the British and Nizam of Hyderabad on the other hand.

Tipu has been seething with anger at what he considered humiliating and unfair terms of the treaty that brought an end to the third Anglo-Mysore war. He was particularly harsh on his detractors and critics.

One day, Tipu received news that one of his Hindu or rather Brahmin ministers, Shamaiah Iyengar had allied himself with the Dowager Queen of the Wodeyars, Lakshmammani, and had joined hands with the British to oust him.

Unlike his father, Hyder Ali, who had respected the Mysore royal family, Tipu had shown scant regard and respect for them. He had a rather strained relationship with the Mysore royals.

Queen Lakshammanni, the Dowager Queen ofMysore, began trying to regain the throne when Hyder Ali usurped power. She started negotiating with the British in the 1760’s with the help of Tirumala Row (It is Rao but the British used it as Row) and Narayana Row. She had assured the two brothers of the pradhanship of Mysore and one-tenth of the income of the state as their salary in perpetuity. When Hyder came to know of this agreement, he imprisoned all their relatives.

After Hyder’s death, the Queen intensified her efforts to place a Wodeyar back on the throne ofMysore. Though Tipu maintained a safe distance from the Wodeyars, he kept a wary eye on them.

When news of the Dowager Queen interacting with the British with help from Shamaiah Iyengar reached Tipu, he decided to take revenge. The agreement signed between the British General Harris of Madras and Tirumaliyengar further infuriated Tipu. Tirumaliyengar was often referred to by the British as Tirumala Row. He was the Pradhan of Mysore.

Tipu ordered his troops to round up all Mandyam Iyengars of Melkote, many of whom were relatives and friends of Tirumaliyengar, and he massacred them in cold blood.

The slaughter was on the day when the Mandyam Iyengars were getting ready to celebrate Naraka Chaturdashi. The celebrations turned into mourning.

The slaughter literally led to the death of Melkote. All people abandoned the temple cityand it soon turned into a ghost town. The 29 Kalyanis in Melkote went to dust, water shortage became endemic and the hills browned and of course Sanskrit lost a home.

To this day, the Mandyam Iyengars of Melkote do not celebrate Deepavali. Unfortunately, there is no mention of the despicable incident in any history book, but even now local folklore and a few accounts of the horrifying event still exist.

Recent research on the incident by Dr MA Jayashree and MA Narasimhan have proved that the incident did take place and among those massacred were women. The research was presented at a seminar at Dhvanyaloka,Mysore.

Quote and reference.

http://samharshbangalore.blogspot.in/2013/04/when-deepavali-is-day-of-mourning.html?m=1