Tiruvaiyaru Sapta Sthanam refers to the seven temples in and around Tiruvaiyaru, that constituted the saptha-pathi (seven steps) at the wedding of Nandi (or Nandikeswara, Siva’s foremost gana and attendant) to Swayamprakshai.
Siva himself officiated at the wedding, held at Tirumazhapadi, and then took the couple to Siva temples in seven nearby towns, representing the traditional seven-steps ritual connected with Vedic marriages. Each of these temples / towns also contributed a requirement for the wedding:

Siva himself officiated at the wedding, held at Tirumazhapadi, and then took the couple to Siva temples in seven nearby towns, representing the traditional seven-steps ritual connected with Vedic marriages. Each of these temples / towns also contributed a requirement for the wedding:
- Fruits from Tiruppazhanam (Apatsahayeswarar temple)
- Food / rice from Tiruchotruthurai (Odhavaneswarar temple)
- Vedic priests / brahmins from Tiruvedikudi (Vedapureeswarar temple)
- Ornaments (Kandi) from Tirukandiyur (Brahmasira Kandeeswarar temple)
- Flowers from Tirupoonthuruthi (Pushpavaneswarar temple)
- Ghee / clarified butter from Tiruneistanam / Thillaistanam (Neiyadiappar temple)
- Celebration at Tiruvaiyaru (Aiyarappar temple)
The occasion is celebrated every year, with a glass-encrusted palanquin carrying the idol of Siva, that starts at Tiruvaiyaru. During this festival, on the day before pournami (full moon) in the Tamil month of Chithirai (April-May), Aiyarappar and Dharmasamvarthini Amman from Tiruvaiyaru invite the deities of six temples nearby to the post-wedding celebrations. The interesting part is, at each temple, they are joined by the deities (utsava murtis) of that temple, and go together with them to the next temple, in their respective palanquins.

First, Aiyarappar and Dharmasamvarthini go to Tirupazhanam. The next stop is Tiruchotruthurai, followed by Tiruvedikudi, Tirukandiyur, Tiruppoonthuruthi and finally, Thillaisthanam.
The Thillaisthanam temple – being the last stop – is kept open through the night, with celebrations and devotional aspects being conducted in parallel. Devotees sing pathigams from the Tevaram all night, and around midnight, crackers are burst to celebrate the events.
The following morning, all of the deities leave for and reach Tiruvaiyaru, where Nandi’s wedding is re-enacted, including a doll that showers flowers on the couple and those present. Later in the evening, all of the deities head back to their respective temples.
Below are the posts on this site, of the Tiruvaiyaru Sapta sthanam temples.