Cerddi'r Carchar
As a poet, his time in jail proved very productive – he wrote 150 sonnets in less than four months – and these sonnets are among his best poetry. Most of the sonnets are without titles in this manuscript, and there are some differences between the contents of the typescript (NLW MS 13693C) and what was eventually published in the printed volumes. Some poems, such as the critical sonnet to 'Golygydd y Cymro' (f. 94) and some of the English sonnets didn't appear in the printed books.
Many of the poems relate to the experience of being under lock and key, and also sympathize with others who are suffering oppression and captivity. See 'Y Negro' (f. 28), 'I Aderyn y To' (f. 80), 'Cath y Carchar' (f. 88), 'Indiaid' (f. 97), [Blodau'r Carchar] (f. 139), [Llygad y Drws] (f. 185), 'Sonedau' (f. 192), 'Troseddwyr' (f. 194), and '2740' (f. 193). The poem 'I Aderyn y To' (f. 80) was translated by Wil Ifan as 'To a Sparrow' (f. 32 and 33).