What is Mudra, Shikka-Mortab?

Original Letter of Raja Shivaji
with Shikka and Mortab

Mudra (मुद्रा) - Seal or the very brief introduction of the person and his designation. Usually it is seen that the text on the seal is little poetic, mostly in Sanskrit or in Arabic.

Shikka (शिक्का) - Principal or opening seal - 

• Raja's or King's seal is found at the top-center of the (start) letter.
• Minister's (Prime?) or Peshwa's seal is usually found in the left margin, in the middle of the letter.

Mortab (मोर्तब) - Closing Seal - 

• Found at the end of last line of the letter -
• Closing seal indicates that nothing can be written after the closing seal is marked. The only thing which is valid, is between the opening and the closing seal.
• Anything written after the closing is seal is considered as forgery and invalid.
• Opening and closing seals can be considered as the virtual boundaries of the letter.

Few examples of seals - 

• Mudra of Shivaji Maharaja - 

प्रतिपचंद्रलेखेव वर्धीष्णुर्विश्ववंदिता । शाहसूनोः शिवस्येषा मुद्रा भद्राय राजते ।।

Like the crescent of the new moon which grows day by day, the one which has great respect towards the life and the people, this seal of Shivaji, Shahaji's son, live, in the heart of the masses.

•  Mudra of Shamraj (Nilkantha?) -

श्री शिवनरपती हर्षनिदान, सामराज मतिमत प्रधान.

• Mudra of Moreshwar (Moropant pehwa?) -

1. श्री  शिवराजेंद्र हर्षनिदान ।। त्र्यंबकसुत मोरेश्वर मुख्यप्रधान ।।
2. श्री शिवचरणी तत्पर त्र्यंबकसुत मोरेश्वर.

• Closing Seal - 

• मर्यादेयं विराजते - This is the end (of the letter)
• लेखन सीमा -  Letter ends here.

Similarly, the Mudras (Seal) of Sambhaji Maharaja and Rajaram Maharaja, elder and younger son of Shivaji Maharaj respectively, are available. Both are in Sanskrit.