The foundation of the Brownes' estate in Sussex was Battle Abbey, which was granted in August 1538 to Sir Anthony Browne three months after it ceased to be a religious house. After moving in, the new owner proceeded to demolish what was not required for domestic contentment and display, and indeed anything which might spoil a good view of the garden. That included the abbey church, which was therefore levelled with the earth. (By contrast the kitchen building was kept on for the new owner's use, and was taken down only in 1685.) The Brownes lived in the Abbot's House which formed the left side of the cloister.

Browne added (by royal grant in 1544) the property of St Mary Overy in Southwark to his haul of former monastic assets. The Fitzwilliam estate, which came to him in 1542, also contained its share of former monastic possessions – Easebourne Priory Waverley Abbey, Calceto Priory and lands previously in the possession of Newark Priory and Syon Abbey. In particular it contained Cowdray palace, part of the manor of Midhurst.

As well as these large holdings of property, the Brownes' estates in Sussex came to incorporate the following: Cocking Manor which the first Viscount Montague bought from Lord Lumley in 1584, some sort of manorial estate in Todham, Heyshot Manor which the earl of Northumberland had sold to Sir Anthony Browne in 1534 and which Montague sold to the earl of Bedford in 1577, Lodsworth Manor (a grant of which was made to Sir Anthony Browne in June 1547), Selham Manor which came to the family through Sir Anthony's father's marriage to Lucy, daughter of the marquis of Montague, Westbourne Manor which came to the family via the same route,Stedham Manor which was acquired by the first viscount from the Dentons (William Denton served as steward to Sir Anthony Browne and the first viscount; his grandson, the second viscount, sold Stedham to the Coldhams, a well-known recusant family), Ashcombe Manor, a moiety of the manor of Clayton (acquired from Richard Culpeper), Poynings Manor and Fulking Manor (in Poynings parish), the church and the so-called manor of Hastings, and chantry land in Winchelsea (all in grant to Sir Anthony Browne), which so-called manor had several impropriate livings, Northeye Manor in Bexhill which Viscount Montague acquired by purchase in 1566, Barnehorne Manor, Wartling rectory (until 1586), Peasmarsh Manor (another grant of 1547 to Sir Anthony Browne but sold off in 1557), Brede Manor (by grant in 1541), Maxfield Manor, and the manor of Sedlescombe (a grant made to Sir Anthony Browne in 1542).