Building of St Olave's Church began in the 13th century and it was dedicated in 1292. It originally served the Estur family as a chapel to Gatcombe House. The manor later passed into the hands of the Worsley family who provided the church with both financial support and a number of Rectors. The font is probably early 13th-century.
The church is noted for its stained glass by William Morris, Dante Gabriel Rossetti, Ford Madox Brown and Edward Burne-Jones, dating from 1865 and 1866. Rossetti founded the Pre-Raphaelite Brotherhood with which Morris, Brown and Burne-Jones were associated.
A carved wooden military effigy with crossed legs in the style of the early 14th century lies in a recess in the chancel, on the north side of the altar. It has an angel by its head and a lion at its feet. Scholarly opinion is divided as to whether it is a genuine medieval figure, recut, restored and embellished at a later date; or an early modern concoction in deliberately archaic style.
At the west end of the church stands a monument to Captain Charles Grant Seely, eldest son and heir of Sir Charles Seely, 2nd Baronet, who was killed in action serving with the Isle of Wight Rifles at the Second Battle of Gaza in 1917. It takes the form of a tomb chest bearing a recumbent effigy of Seely, who is depicted in uniform and with legs crossed in allusion to his service as a modern-day 'crusader'. It was the final work of the eminent sculptor Sir Thomas Brock, and was unveiled in 1922. In 1927 it was vandalised by a local woman, Nellie Kerley, who appears to have been aggrieved by the contrast between the memorial's grandiosity and the relative neglect of the memory of her brother, who had also died in the war. The damage to the effigy's face and sword-hilt is still clearly visible.
The churchyard contains two Commonwealth war graves, of an officer (Flight Lieutenant Antony Basil Langton) and a sergeant (Sergeant William Reuben Cooper) of the Royal Air Force Volunteer Reserve from World War II.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.