In 1448, a prisoner named Thomas Brodeley escaped from pre-trial custody in Wakefield, Yorkshire and made his way to the (impressively large) parish church of Wakefield to take sanctuary.
The sheriff of Yorkshire seized him from the churchyard and took him to the presumably more secure prison in York castle. The archbishop of York promptly sent a letter to Henry VI complaining of the breach of the church’s sanctuary, and the king duly sent a writ to the sheriff and the gaol-keeper commanding them to restore Brodeley to the Wakefield church. You might be noting a theme in these cases: Henry VI as defender of “his” sanctuaries, as he sometimes called them.
TNA, SC 8/236/11757; SC 8/236/11761. Top image, Henry VI in the 1440s: from http://www.bl.uk/manuscripts/Viewer.aspx?ref=royal_ms_15_e_vi_f405r
Sanctuary Seekers in England, 1394-1557 
