Records relating to the Barony of Kendale, CWAAS, W Farrer & J F. Curwen (eds) available on British History Online (also Supplementary Records).
Cumbria County History Trust has published a "Jubilee Digest" for the township of Helsington and completed a draft VCH township history.
Magna Britannica et Hibernia.Volume 6: Westmorland by Thomas Cox (Vicar of Bromfield, Essex) 45 pages, printed in 1731. Transcription by Sarah Reveley, Joan Fisher and Lisl Schoenwald:
"Helsington, the Lordship and Estate of Marmaduke Thweng, a Parliamentary Baron, who sat in Parliament with the Barons from 35 Edw. I to 16 Edw. II. He made over this Manor, and some other Estates, to William his Son and Heir in his Life-time, and left him many more at his Death, which happened 16 Edw. II. William his Son and Heir had Summons to Parliament 18 Edw. III but never after. He died without Issue 15 Edw. IIII. And left this and his other Estates to Robert his Brother, a Clergy-man, as he did for Want of Issue to his Brother Thomas, A Clergyman also, and Rector of Lythum, who died possessed of them, and left them all to be divided between the Posterity of his three Sisters, but to which of them this Manor in the Partition came, is not particularly set down in our Author."