Bhagwan Shri Mahavir swami, before becoming a Tirthankar, had to pass through 27 birth.
1st previous birth:-

In the west of Mahavideh of Jambudweep in Mahavipra vijay, there was city named Jayanti. King Shatru Mardan ruled there, In his city, there was a place called Prithvi pratishthan, whose officials name was Naisar.

Once, the king ordered Naisar to get woods from the jungle. Many people accompanied him. In the afternoon, all were having lunch, when they saw a sadhu. Sadhu had an escort with him, but the escort had gone ahead, & sadhu had lost his way. When Naisar saw the sadhu, a great devotional feeling evoked in his mind. He approached the sadhus, prayed & came to know that, they had lost their way & were not only hungry but also very very thirsty. Naisar offered them food & water & again saluted them & showed them the right path.

2nd birth:- (Swarg)

He became a Dev in Devlok.

3rd birth:- (Marichi)

Naisar was reborn as the prince of Chakravorti Bharat, named Marichi, Once in Ayodhya city, Bhagwan Rushabhdev came, gave his first preachings & instructions. Marichi got deeply influenced by Bhagwan Rushabhdev & took Diksha.

4th birth:- (Swarga)

He became a Dev of higher grade in Bhramlok.

5th birth:- (human being)

He was reborn as Kaushik in Bhramin family. His life span was more than 80 lakhs years.

6th birth:-

He was reborn in Thuna city as a Bhraman named Pushya Mitra. His life span was more than 72 lakh years.

7th birth:-

He became a Deva in Devlok.

8th birth:- (Human)

After becoming a Deva, the atma of Naisar became a Brahmana in Chaitya Sannivesh. His life was for more than 64 lakh years.

9th birth:- (Swarg)

He became a God in Devlok.

10th birth:-

The atma of Naisar became a Agni Bhooti Bhraman & later on took Diksha. His life span was for more than 56 lakh years.