At the rear northwest corner of St John's Church grounds, there's a small gated cemetery partly paved with 18th-century grave stones. The centrepiece of this area is a hollow thick-walled octagonal cenotaph on whose inner wall you'll find the grave of Job Charnock, the (Western) 'founder' of Calcutta. Charnock died in 1693, just three years after his third visit to what would become Calcutta. The grave dates his demise to January 1692 (not 1693), as years were then considered to start in March.
Mausoleum of Job Charnock
Kolkata (Calcutta)