A Study of the Strood by W.E. Duane. Chapter 4. 17.

The Early Settlement of Mersea Island contd.

... text of the A.S.C. A 895 says:-

[Note 1] "1on an island paet is ute on paere sae, paet is Mersig." The Anglo-Saxon Chronicle [Note 2] describes how, when the Danes were turned back from Wales with the booty they had captured there, "they went so that the English army could not reach them, across Northumbria and into East Anglia until they came into east Essex on to an island called Mersea, which is out in the sea."
[ Note 3] "Then that same year in early winter the Dames who were encamped on Mersea rowed their ships up the Thames and up the Lea."

The Strood is given as "Strodeway" in the Catalogue of Ancient Deeds 1455 and its meaning as "marshy land".

The last source consulted [Note 4] lists the name as deriving from the Old English 'Mere' meaning 'mere or lake. The meaning sea is rare, but found here in Mersea. 'Eg, icg,eye' are all from Old English, meaning island. 'Meresaie' as named in the Domesday Book, is listed as 'the island in the sea'. In the same book, the name Strood is said to derive from the Old English, 'Strod or Strop' meaning 'marshy land overgrown with brushwood'.

These early names surely point to the fact that Mersea has undoubtedly been an island since the first inhabitants ...

Note 1 Page 320 Place-Names of Essex.
Note 2 Page 187 English Historical Documents Vol. 1.
Note 3 Page 188 English Historical Documents. Vol. 1.
Note 4 Oxford Dictionary of English Place-Names

Date: 1965