In June 1580, my ancestor Sir Nicholas White set off as part of an expedition from Dublin to pacify what is now County Limerick and County Kerry in the wake of the Second Desmond Rebellion. He wrote an account of the expedition which was published in 1872. Since it's the exact anniversary of the expedition over the next few weeks, I'm posting the relevant excerpts daily. The first includes the covering letter to Lord Burghley.
MY singular good Lord, — I do here send your Lordship a diary of our late journey in Munster, from our first setting forth from Lymericke until our return thyther agayn ; and whence, from my last letter of the last of Maie, I promised to send your Lordshippe a booke of all the houses, castells, and landes belonging to the Earldom of Desmond, and such as be in rebellion with him. It may please your Lordship to understand, that I cannot as yet perform the same for want of good information.
Comment: They had presumably arrived in Limerick by sea from Dublin, the land journey being blocked by Desmond's forces. The expedition is a penetration of hostile territory from a friendly port. Both Askeaton and Kilmallock had been abandoned shortly before by the Desmond forces. The Dublin/Ormonde army was clearly sufficiently numerous to divide their forces, Ormond going south and Grey west.