Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

The political turmoil continued. John began to explore an alliance with the French king Philip II, freshly returned from the crusade. John hoped to acquire Normandy, Anjou and the other lands in France held by Richard in exchange for allying himself with Philip. John was persuaded not to pursue an alliance by his mother. Longchamp, who had left England after Walter's intervention, now returned, and argued that he had been wrongly removed as justiciar. John intervened, suppressing Longchamp's claims in return for promises of support from the royal administration, including a reaffirmation of his position as heir to the throne. When Richard still did not return from the crusade, John began to assert that his brother was dead or otherwise permanently lost. Richard had in fact been captured en route to England by the Duke of Austria and was handed over to Emperor Henry VI, who held him for ransom. John seized the opportunity and went to Paris, where he formed an alliance with Philip. He agreed to set aside his wife, Isabella of Gloucester, and marry Philip's sister, Alys, in exchange for Philip's support. Fighting broke out in England between forces loyal to Richard and those being gathered by John. John's military position was weak and he agreed to a truce; in early 1194 the king finally returned to England, and John's remaining forces surrendered. John retreated to Normandy, where Richard finally found him later that year. Richard declared that his younger brother – despite being 27 years old – was merely "a child who has had evil counsellors" and forgave him, but removed his lands with the exception of Ireland.
Who did John explore an alliance with?