He later compiled one of the earliest histories of the county of Cheshire and as a result of this became involved in a controversy with the Mainwaring family.

He was an active and conscientious justice of the peace and used his position on the Bench to expound his staunchly conservative and Royalist political views.

In this capacity, according to a modern historian, he harangued grand juries with warnings on the constant dangers of sedition and revolution, and the need to maintain a vigilant watch on all Roman Catholics, especially Jesuits, as well as republicans, Puritans and anyone else who threatened the existing social order.

Whereunto is annexed a transcript of Domesday-Book, so far as it concerneth Cheshire; it is usually referred to with the shorter title of Historical antiquities.

In the book, Leycester presented a discussion relating to the legitimacy of Amicia, the wife of Ralph Mainwaring, as to whether or not she was the lawful daughter of Earl Hugh Cyveliok.

[4] This led to a dispute with Sir Thomas Mainwaring of Peover, one of her descendants, who in 1673 published a Defence of Amicia.

He produced a musical treatise entitled Prolegomena historica de musica P. L. and a theological dissertation On the soul of man.